The iPhone Dev Team has officially announced that a software unlock for the iPhone 3G has been accomplished and that they’re just working on packaging it nicely for release. We’ve sort of known this for a while now since it was a number of weeks ago that they ran arbitrary code on the baseband, but the important part of THIS announcement (coral) is the release date, New Years Day!
There is a caveat to this release, though – if you updated your phone to iPhone OS 2.2 the official way via iTunes, you’re out of luck. As explained in this post (coral), update 2.2 also updated the baseband to an uncracked version. If you followed the instructions in that post, you’ve got the old, cracked baseband, and you’ll be good to go new years day. Otherwise, I suppose you’ll just have to wait until they re-crack it.
In general, the best rule to follow is to simply not update your phone until you’ve heard from the dev team what the update entails.
Finally, you may run into potential issues if you’ve already updated to Mac OS 10.5.6, but it appears that they already have some workarounds posted. I’ll let you know what my own experience is once I get my laptop back from the Apple Store where it’s getting repaired and get this release on new years.