Considering that it's in beta right now and that the iPhone Dev Team is working on it for the iPhone, and I'm sure the iPod touch version will follow behind, we'll find out soon enough. Be patient...
2.2 will be jailbreakable on the 1st gen ipod only at the minute, the jailbreak relies on a hardware exploit in the 1st generation ipod touchs so any future firmware release will be jailbreakable for the first generation iPods.
Is 2.2 even out yet? No... At least wait until it's released then bother asking. No point in jailbreaking it when no one has used it yet, apart from beta-testers.