The 2TS places are called Signature Dining Locations. They are more upscale, in other words more pricey than your regular meals, which explains the requirement of 2TS credits.
Here's a link to this year's brochure:
http://adisneyworld.disney.go.com/m...09 Disney Dining Plan - Walt Disney World.pdf
The list (I may have missed a couple) is:
In the Resorts:
Jiko (AKL)
Flying Fish Cafe (BWI)
California Grill (CR)
Hoopdeedoo Revue (FW)
Mickey's Backyard BBQ (FW)
Citricos (GF)
Narcoossees (GF)
Spirit of Aloha Dinner Show (Poly)
Artist Point (WL)
Yachtsman Steakhouse (YC&BC)
In the Parks:
Hollywood Brown Derby (DHS)
Cinderella's Royal Table (MK)
AK & Epcot do not have any 2 TS meals.
The only character meal that is 2 TS is CRT.
Basically, each Deluxe resort has at least one Signature Restaurant, but the majority of Dining Plan qualifying restaurants are a single credit.