Ive had my iPhone for a couple weeks now and I've found some awesome apps that I'm going to showcase here. Some are really common (like camera+) so I will try and focus more on the less known apps.
5. NHK World Live
I watch the NHK world stream all the time. NHK is a television network in Japan very similar to CBC here in Canada. NHK World has all its programs in English and they all focus on Japanese news, culture, and entertainment. I specifically like the Tokyo Eye, and J-mello programs. This app simply streams the TV Chanel to your phone. Its great for wasting time in class, and its free.
A great app for listening to podcasts. you can download or stream them on wi-fi or 3G, and you can change your settings if you don't want the app using your 3G data. I listen to a lot of podcasts so this app was well worth the .99$
This is a pretty fun app. Its probably most using for people doing presentations and want to use their phone to move to the next slide but its perfectly using just on the desktop. This app lets you use the phone as a mouse and keyboard for your computer. You download the app on the phone and computer then connect through wi-fi. Works pretty well but the 2 finger scrolling doesn't move the page down much on the desktop. This app has a free and paid version. The free version works fine, the only thing the paid version adds is the ability to have a full screen touchpad or keyboard.
2. Tunein Radio
This is a pretty popular app and for good reason. This app lets you stream radio over the Internet to your phone. They have a lot of different radio stations, from your basic CBC radio to a bunch of Japanese radio stations that can be fun to listen to. Works best on a stable wi-fi connection but can be done over 3G too if you have the data for it.
A Japanese dictionary. It might not be using for everyone but for someone who is studying, or reads a lot of Japanese this is a excellent app. It works in a lot of ways. You can type English and get a translation, or just search for words in either language. But what makes this app really great is the kanji dictionary. You can search for radicals individually and get a list of which characters contain those radicals. You can search by JLPT levels, the SKIP pattern, and just by looking up either reading. This is a really using app for me, and its free. Its a large app though at about 500MB buts I would rather have all that info there instead of transmitting over data or wi-fi.