iPhone 3G Software Unlock “Yellowsn0w” Released

Here’s the gyst:

1. The unlock now ONLY works on baseband 02.28.00. That is, the baseband that comes with the standard iPhone OS 2.2 update.
2. The unlock is a daemon. That means it runs in the background and, every time your phone restarts, it re-injects the unlock code. It’s not persistent – as soon as your phone becomes un-jailbroken (an update, for example) it will go away. Watch out.
3. The unlock program installs via Cydia, NOT any of the jailbreak tools.

How to get it:

1. Make sure you’ve got iPhone OS 2.2 and the latest baseband. Do a standard update or restore in itunes, then re-jailbreak your phone.
2. Add Cydia source http://apt9.yellowsn0w.com/ (or if you’re old school, installer repo http://i.yellowsn0w.com/)
3. Find and install the package Yellowsn0w.
4. Enjoy your unlocked phone (you can throw in whatever SIM you like now!)

For more/more detailed info, the offical post is here (coral)