The Thunderbolt has been in the books for some time now with the launch coming soon, a group of accessories just began arriving at BestBuy. The picture above shows BB’s Thunderbolt based accessories and points at an impending release. The usual period between an accessories arriving and a phone being put on their shelves is somewhere in the weeks, so at this point, the best we can say is February is the definite month.
Source (ThunderBolt, Inspire accessories show up at Best Buy ahead of launches | Android Central)