Well, as everyone would know, I used to be very anti-apple, and touted the iPhone as a devil phone. But since I bought one, my judgement has changed, and it really is quite a nice device.
The first thing I did when I got the iPhone, was JailBreak it with QuickPwn. This allows you to run 3rd party applications on the iPhone. If your thinking about doing it, I would highly suggest it.
After JailBreaking your iPhone I would suggest installing the following applications, you may or may not like them, but I sure do.
1. AppShare and Installous (Homepage)
AppShare is like a version of the AppStore, but cracked so software is free. Installous allows you to download / install ipa files directly from Safari.
2. BeeJive IM (Homepage)
BeeJive IM is basically an “All-In-One” instant messaging client, which allows you to connect to multiple protocols (MSN, Yahoo!, AIM) e.t.c.
3. BlogWriter (Homepage)
Is basically blogging software for the iPhone, can connect to multiple blogs, upload pictures e.t.c.
4. Bubblets Tilt (Homepage)
This is just like the famous Bubble Breaker for Windows Mobile, ported across to the iPhone, I love this game.
Well that should keep you going for awhile, more to come soon!