We've received a couple comments/emails asking why the Textbook Revolution site's been down and when it's coming back. Here's the answer from Jason:
"My old webhost managed to destroy my site, and reconstructing it has proven to be far more difficult than I'd hoped. Not to fear, Textbook Revolution will be back in the near future. Thanks for your concern and sorry for the delay in connecting you to the free books."
So not to fear, TBR will be back soon...
In the meanwhile, you might want to check out the free textbook google custom search.