For the rebels and hackers of you out there, the iPhone Dev team have released the jailbreak for the iPhone 3G.
The jailbreak is currently a multipart release and only currently available to Mac OS X users via PwnageTool, with QuickPwn on the way for the Mac and Windows shortly.
You can find full instructions here (make sure you read them thoroughly.
You should know if you are using a 3G iPhone with yellowsn0w then you should not use PwnageTool right now, also – you lucky new iPhone 3G S owners – the jailbreak will NOT work with your handset just yet.
H/T Simon Wicks