The iPhone Dev Team (yup, they're still around) has been a bit quiet of late, noses to the grind stone and fingers typing speedily into their respective Terminals... seeking a 3G iPhone software unlock. While they have made progress (running unsigned code on the 3G baseband, among others), a software unlock for the 3G has yet remained elusive.
With the 2.2 firmware being released soon, Apple again has set things in the update to nix the jailbreak-ability of it. The best thing, as always, for jailbreakers is to WAIT UNTIL ITS SAFE TO UPGRADE, then use the guide which we'll pop out to do so. This has typically been within days, sometimes hours, of the new firmware release.