Chad's videos: google course saver, the link is in the forum under Chad's videos, then premium videos
For $25 you get 3 months access to one set of the videos you pick, same price for another, etc. Or you can subscribe for $30 = 1 month, $50 = 2 months, etc for access to all the videos.
Get a biology textbook (pref Campbell's 8th edition, or earlier? It's what the ADA uses as a ref). Many people recommend Cliff's AP biology, Kaplan BB, etc. DAT Destroyer comes with a bunch of questions. But from what I've read, it doesn't seem like any one of these references was the perfect help by itself for the actual DAT, so I'd again suggest the textbook as your primary.