The new TMNT teaser is up, along with an empty distributor website.  To find more info you can look at the Imagi site the company handling the 3D Animation.

The turtles actually look pretty good, but its not too clear how closely the will resemble their PG rated incarnation from the early 90s movies or the R rated version from the original comic books.  This is essential to how they use their weapons.  Hopefully Leonardo will not have to backhand foes with his blades like PG-13 Wolverine in X3.