iPhone 3.0 OS is jailbreakable on all devices. It’s just those using 3G yellowsn0w that have to show some restraint and wait for PwnageTool to create a custom IPSW that avoids the baseband update. If you are using yellowsn0w, do not update or restore to iPhone 3.0 firmware. You will lose yellowsn0w and find yourself unable to revert the baseband to get it back.
DevTeam has announced that iPod Touch 2G is finally jailbreaked.
The raw patch to the firmware that transforms the “tethered” jailbreak into an untethered one was released here but it’s not yet packaged up into the PwnageTool or QuickPwn flows. But other threads there are pulling together tutorials and other tips for those of you anxious to try this out now. For the curious, the hole itself is explained here.