I phone3g

[sugat]

how to change my widgets and background?I do not like the present set up. Please adv.

[shutter13]

Jailbreak.

[Hawk]

Currently there is no LEGAL way to customize your phone. That being said, you can do what's called Jailbreak, which opens the phone's OS to apps not approved or that violate the SDK. (Software Developers Kit).
If your phone ever has a problem, simply restore to stock settings and setup as new.
While there are thousands of jailbroken phones out there, it's not 100% safe. There is a slight possibility that you could render your phone in a state where you have to return to Apple for service. There is also a performance issue where some users experience lag opening and using apps. They will tell you it's worth dealing with. Others will tell you it's not. It's up to you.