We have already posted a summary of iPhone dev team blog post where it has been mentioned clearly that iPhone 3G users should not upgrade to firmware 2.2.1 as it will update your baseband to 2.30.03 and your will lose ability to unlock iPhone 3G with yellowsn0w.
That’s the only condition for firmware 2.2.1 for rest of all cases you can upgrade your iPhone and iPod touch to firmware 2.2.1. as we already have QuickPWN 2.2.5 and PwnageTool 2.2.5 to jailbreak your iPhone and iPod touch well windows users need to wait for some time as this is only available for Mac Users.
Download QuickPWN 2.2.5 For Mac
Download QuickPWN 2.2.5 for Mac (Torrent link)
Download PwnageTool 2.2.5 For Mac
Download PwnageTool 2.2.5 For Mac (Torrent Link)
Download link for QuickPWN 2.2.5 and PwnageTool 2.2.5 for Windows Coming soon