It's true that you need 3.0 to activate the bluetooth chip in the iPod Touch 2G, however some (if not many) bluetooth headphones come with adapters that plug into your iPod.
If you follow the link in the first reply of this tread, you will see it is compatible with ALL iPod models. Click on the photos and click the last one to see the adapter. All it is, is a regular headphone plug with a bluetooth transmitter on the end. 🙂 Having 3.0 will just not require said adapter anymore.