TVP has no flavor of its own; it needs to be rehydrated and flavored (both can be accomplished in the same step), then added to dishes.
TVP comes in 2 forms: ground for ground beef substitutions, and chunked for chunked chicken substitutions. Using TVP, one can make vegetarian versions of popular dishes like chili, sloppy joes, tacos, burgers, etc...
TVP can be found in health food stores and larger supermarkets.