In general, all books, movies, yarns, etc. that I talk about are items that I bought, checked out from the library, or was given by someone other than the publisher/manufacturer/etc. The main exception is books published or distributed by the University of Texas Press, my employer.
As of the effective date of the new FTC guidelines (1 December 2009), if I receive a book/movie/yarn/whatever for review from the publisher/author/manufacturer/entity with a direct financial interest in the item, I will state this in the post where I review the item.
The University of Texas Press does not give me books for review (though of course I can borrow copies out of the editorial library, and the employee discount is quite good, especially in December), but they are my employer. Any opinion I state about a UTP book is my personal opinion and not an official statement of the University of Texas Press, the University of Texas at Austin, or the State of Texas.