If you were wondering how you could get your the new iPhone 3.0 OS unlocked, the iPhone Development Team have unveiled new set of instructions to do so using redsn0w.
Redsn0w is a multi-platform jailbreaking and unlocking tool which lets you claim your iPhone 2G, iPhone 3G and iPod touch first and second generations. However, you should not attempt to unlock your brand new iPhone 3G S with redsn0w, for it is not supported yet. If you have an iPhone 3G S which you bought very recently, what you could do is wait for the ultrasn0w to be released.
Nevertheless, you could use the instructions given for redsn0w to unlock any of your devices running on OS 3.0 except iPhone 3G S. The iPhone Dev Blog not only has detailed instructions but also links to torrent files that allow you to download the tools from reliable mirrors.
If you were wondering how to Unlock your iPhone 3G with yellowsn0w (for the previous iPhone Operating Systems), we had written an article describing how you could do that many months ago. You could also learn How to Unlock your iPhone 3G in just Five Minutes. Whatever you do, you must make sure you follow the instructions properly as getting something wrong might put your device under jeopardy and render it useless to be used.