Here are a couple of handy resources:
Thunderbird Sport Riders Network
Web Bike World TBS Page
For the full manual, you'll probably want to see if you can get it from a dealer or ebay. I've got the little insert that goes with the TBS to show some of the adjustments specific to the TBS suspension and such. If you can't come up with it, shoot me a PM or e-mail and I'll run you a copy. You can also buy the Haynes manual. It's a good resource. The Motor Bookstore link that comes up at the top of this Rat.net site is a good place to get that book.