JLT on the iPhone: The same dictionary program used in the Complete System, EBPocket, is now available as an iPhone app (and it works perfectly on the iPad and iPod Touch, too). With its advanced search features, expandability, and fast performance, it's the best dictionary app for Japanese on the iPhone. For only US$4.99 or 600円 (perhaps those prices need to be updated to reflect the current exchange rates!), you should definitely spring for the Professional version; the free version is limited to only the Forward and Backward search types--it lacks the Cross search that adds so much to Eijiro, and a few other features. (For now, see the Windows Mobile EBPocket page in the JLT documentation for information on the search types and features of EBPocket; more information on the iPhone version will be coming to this page soon.) With EBPocket, you can use all the great JLT dictionaries: Edict (heavily customized by JLT to give much better English-to-Japanese search results than the standard Edict that comes with the app and is widely available elsewhere); Enamdict, a huge dictionary of Japanese proper names, including place, personal, and commercial names; Conjugations, which not only helps you conjugate verbs but also lets you enter a conjugated form to find out what tense of what verb it is; Kanjidic, which is exactly what you'd expect--it also includes stroke order diagrams to teach you how to write each kanji properly; and the crown jewel of the JLT system, the JLT version of Eijiro--I've added yomigana to almost every kanji-containing word in both the E-to-J and J-to-E parts of Eijiro, not only making it far easier to read the results of any search but also making it possible for the first time to look up a Japanese word in Eijiro by how it's pronounced as well as by how it's written. You can also add some of the excellent commercial dictionaries in EPWING format like Daijirin and Koujien (both Japanese-Japanese dictionaries), the intermediate and large versions of Kenkyusha, the Nouveau Petit Royale French<>Japanese dictionary, and others; plus any of the excellent free EPWING dictionaries, some of which are described elsewhere on the site. I'm not sure yet, but it looks like the iPhone version of EBPocket is limited to a total of 8 dictionaries.
How good is it? The program and dictionaries are superb. EBPocket Pro and the JLT dictionaries are far and away the best Japanese dictionary system you can get for your iPhone. The limitation is the iPhone itself. In short, the iPhone is fantastic for someone who doesn't have to read much Japanese or for someone who's already mastered the Joyo kanji, and it's a great backup for someone who has a full JLT system but may not want to carry it with them 24/7--but it's not good enough, by itself, for someone seriously studying Japanese or to be the main dictionary for someone living in Japan. If you're studying hard or if you want something you can use to understand a product label, the buttons on your washing machine, or a sign you encounter, the iPhone will often let you down. Why? The iPhone has mediocre Japanese support, and you can't add better Japanese support for both technical (no multitasking, for anyone wondering) and philosophical reasons (Apple doesn't allow apps that duplicate built-in features, like the Japanese support). The iPhone has only a keyboard IME for Japanese entry--you can enter kanji and kanji compounds only by pronunciation. You can use the tools in Kanjidic to look up unknown kanji there pretty easily, but it's a pain to use that to enter a word with several kanji so that you can look it up in a word dictionary. In short, if you're reading and you see a word you don't know, it's difficult use the iPhone's Japanese input to enter the word and look it up (and since the words you don't know are the ones you most want to look up...). If you only have to do that once in a while, the iPhone is fine, but if you're doing it regularly, it'll get frustrating pretty quickly. You can also use the Traditional Chinese handwriting entry system to write in kanji, but all too often, it just doesn't work: first, the entry system doesn't work as well as the system in Windows Mobile (drawing a complex character in a small area with a big fingertip is obviously less than ideal, though it does work much better than one would expect); second, a lot of kanji don't exist or are quite different in Chinese, so you can't find those at all through the Chinese handwriting system (kanji came over from China 1500 years ago--a lot of characters have changed since then in one country or the other); finally, of course, you can't enter hiragana or katakana through the Chinese input method, so entering a word that contains both (any verb, for example) requires jumping around among the input methods--assuming that the you're able to find the kanji part through the Chinese entry system, of course. But, again, if you don't need to read written Japanese too often, then the iPhone is excellent.
I have an iPhone; is it worth putting EBPocket and the JLT dictionaries on it? Definitely. The app costs only US$4.99, and you can get all the JLT dictionaries except Eijiro for free. If you already have the JLT Complete system, then you've already got the JLT version of Eijiro, too. You can use the JLT system when you're studying or need something more capable, but still have some capability when you're out in the world with just your iPhone. If you don't have the Complete System, you can buy the JLT version of Eijiro in a package with the other JLT dictionaries and 3 years of support by email for 5000 yen. Casual users may be happy with just the free dictionaries.
I don't have an iPhone yet; should I get one? Again, if you don't need to read Japanese very often, then EBPocket and the JLT dictionaries on the iPhone will meet your needs beautifully. If you're studying Japanese pretty seriously or if you live in Japan and want something to help you read the Japanese you run into all day long in your daily life, you'll need something more. I'm the first to admit that, aside from Japanese dictionary stuff, the iPhone is a great little device, and a whole lot of iPhone users simply fall in love with their phones. So for many, the best solution may be to have both--the best phone to have with them all the time, and the best dictionary to bring along when they need it. I'm a 6' tall guy, so you'll usually find me out and about with my phone in one front pocket of my jeans and my JLT Axim in the other--for me that's pretty comfortable (if you don't need a smartphone, then you can get a pretty small phone these days). If you want to have the best of both worlds all in one device, then the ideal solution would be a Windows Mobile phone. If you live in Japan, you can easily find a Windows Mobile SmartPhone with the Japanese version of the OS. It's already got Japanese support built in, so just follow the directions to download and install EB Pocket and my dictionaries and you'll have everything up and running in about three minutes. If you can't find a Japanese phone where you live or if you prefer a phone with an English OS, please note that it can be difficult to add Japanese support to an English phone--that's one of the reasons so many people get the JLT Complete System.
Installation: Full instructions in Japanese are on the EBPocket home page, but here's a quick guide in English. It may be helpful to consult the screenshots on the home page, even if you'd rather follow the English instructions here.
Here are the standard JLT dictionaries. Other than Eijiro and Conjugations, the JLT dictionaries can be downloaded for free from their respective pages. Edict, Enamdict, and Kanjidic are all based on the dictionaries of the Electronic Dictionary Research and Development Group, under the fearless leadership of Prof. Jim Breen, at Monash University in Australia (copyright and license terms), and Conjugations, while put together by JLT, uses data from the same source. See the pages below for more information and to download the free dictionaries.
There are also a wide variety of other dictionaries available around the web, everything from English-English dictionaries, Sanskrit-English, and archaic kanji to various encylcopedias, Shakespeare, and texts and dictionaries for various religious studies (the Buddhist terms dictionary is especially impressive). Some of the most useful are listed here on my site, along with a few others I've converted from free and open sources and data made available.