January 2, 2009 Dev-Team has made good on their promise of an unlock for the iPhone 3G, with an unexpected bonus: it will unlock phones running the latest firmware (2.2) and baseband (02.28.00).
To unlock your iPhone 3G, head over to the Dev-Team blog for instructions, and make sure you understand that the version number of 0.91 implies that this is beta software that may not function with your SIM card of choice.
We suggest those of you who aren't comfortable with tinkering with the inner workings of your phone via a command line wait for a more mature release of the software, and possibly a confirmation from another user that SIM cards of the network you'd like to use will function correctly with the unlock.