If you are interested in Jail Breaking... this is where you would get your info on how to do it.

http://blog.iphone-dev.org/

They are the team that finds the hacks and jail broken options. They are pretty reputable.

Also, pros in jailbroken iPhone, you can get Apps like a Video Camera if you don't have the 3gs. Also, there are some pretty nifty designs you can do, by changing all your icons and their look or even making it look just completely unique to how you feel.

I myself, will be jailbreaking my iphone after the 25th of this month because we get the MMS deal.

The reason why I'm waiting is because after you jailbreak it, if any new updates come out it has to be re-jail broken. I don't like going through the hassles of doing it twice. The dev-team comes up with the jailbroken procedures and makes it pretty easy to understand. Most cases its holding the power button for 10 secs, then the home button for 5, and so forth. The options are on your computer screen so its easy to understand.

Some apps that you might like is...

SBSettings, which allows you to swipe your finger at the top of your home page and from there it drops a menu which allows you access to power options, for example, restart, turn off, that sort of thing. Also, from that you can turn on and off blue tooth, wireless, 3g, place it in airplane mode. Also, it can hide icons you don't use. It is just very nifty.

Many other nifty applications and set-up you can do. Research before you do it. Its simple and easy to do, but it is not for everyone. Some are already confident and satisfied with it the way it is. Hope this helps.