This show was originally announced months ago, but there's now finally a trailer. The trailer will premiere on TV during the season finale of The Legend of Korra on Saturday, but you can see it online now at Entertainment Weekly:
Trailer at Entertainment Weekly
Not too keen on the animation style, but I might be able to live with it if the show is good enough.
Jason Biggs as Leonardo
Sean Astin as Raphael
Greg Cipes as Michelangelo
Rob Paulsen as Donatello
Never thought Paulsen would be voicing a Turtle again, though it's a different one this time.