They've finally delivered: the Dev Team has released the Ultrasn0w full unlock for last-gen iPhones running firmware 3.0.
The instructions are nice and short:
1. Ensure you have upgraded to iPhone OS 3.0 2. Jailbreak your iPhone 3G using redsn0w or PwnageTool (this will also install Cydia/Icy) 3. Run Cydia or Icy 4. Please add the repo repo666.ultrasn0w.com to Cydia or icy 5. Search for ‘ultrasn0w' in cydia or icy and install ultrasn0w 6. Reboot your iPhone 3G 7. T-Mobile USA users should disable 3G before using ultrasn0w 8. Enjoy
It bears repeating that this hack will not work on the iPhone 3GS, though it will work on 2G and 3G models. The Dev Team is obviously working on this, but they're not giving any fresh indication as to when a fully compatible tool will come out. [Dev Team—Thanks, Alexandru, Stephen, and everyone else!]