iPhoneRingToneMaker to make ringtones
Jail break Ur iPhone to get installer/cydia and do a search on google to get sources. Some websites like, iModZone and xsellize will give u a premium/VIP source to download full/cracked app store games and those not listed in app store if u sign up to there forum and donate.
If u have a 2g (not 3g) iPhone and have not updated to FW 2.0 u can use SwirlyMMS to send and receive MMS.
Cycorder and iPhone Video Recorder can be used to record video on ur iphone, but u have to jail break ur iPhone. Cycorder quality is better and it's free. iPhone video recorder is free if u can find the cracked version.
Snapture works much better than the camera app that comes with the iPhone. It's free if u can find the cracked version. U can zoom in change the pic from color to grey scale/what ever else.
3G iPhone's cannot be unlocked by software PERIOD. there are chips out there that u put in with ur sim card, but I don't know if they work or just some straight bullshit.
If u can get a hold of a 2g(not 3g) iPhone and don't want to switch to AT&T then u can unlock the iPhone to use with T-Mobile and I think there's a way to get it working with other carriers who don't use sim cards (Not sure)
Winter Board can be used to modify the UI of the iPhone spring board/battery/locked screen.
If u have a 2g (not 3g) iPhone and wish to dramatically improve ur speaker volume, then get a needle and poke a hole in it. Or take the back bottom cover off and remove the tape entirely. This does expose ur iPhone to getting a lot of dust on the inside. DO NOT TRY ON 3G iPhone!!!
hopes this helps.
JAIL BREAK AND UNLOCK AT YOUR OWN RISK