iClarify has the whole instruction written down to specifics in iPhone | How to Unlock/Jailbreak Your 2.x.x 2G iPhone Using QuickPwn (Windows) article. Very through and easy to follow. Give it a try if you already have iPhone and not yet hacked it. =)
If you are looking for any additional hack or support or updates, macrumors forum provide superb community which provide information for you. Go check it out.
Quoted article below:
|iPhone | How to Unlock/Jailbreak Your 2.x.x 2G iPhone Using QuickPwn (Windows)|
These are instructions on how to unlock/jailbreak your 2G iPhone to the 2.2 iPhone firmware using QuickPwn for Windows. Before beginning make sure you have updated to iTunes 8.0.2.