Its available for pre-order at TLG, has been for about two weeks now. I believe I also read that it had been sent off the printers when I first saw the pre-order option, so I would guess any time now.
Since Necromancer is having a big sale of their TLG inventory due to their (TLG's) warehouse being full of new C&C material, maybe they have gotten the stuff back from the printers and are sending out the pre-orders as well as stuff to the distributors.
The Troll Lords website says that it is in from the printers and shipping to pre-orders since March 9. Some trade show puts off the shipping to retailers until March 21, IIRC.
I finally got a chance to read through a good portion of Blacktooth Ridge and I really like what Im seeing. Some nice open ended goodness here. Will try to report more when I give it a thorough read through.
Oh, by the way, the Episode III trailer kicked me in the jimmy and took my lunch money. I cant wait to see this film!