WinPwn 2.5 makes it stupid simple to jailbreak or unlock your iPhone. Note that so far, you can only jailbreak the iPhone 2G. An unlock method for the iPhone 3G is not available yet but check out my blog every once in a while as I will be staying on top of that and I will be informing you.
So, how to jailbreak the iPhone? Pretty simple. I just created a guide that will show you every step of the process: jailbreak your iPhone with WinPwn 2.5.
This tutorial works for iPhone 2G and 3G. Only a few steps slightly change. Read the tutorial and leave comments.