To be honest, I don't like the Unofficial Guide. We are planning a trip to DL this year, and I have had a heack of a time finding any books on DL here in Orlando! I went to 3 different bookstores and they had plenty on WDW (go figure). I found one when I went back to PA for Xmas, and I think it's called the Everything Guide to DL. It also includes Knotts, Magic Mountain and Universal, as well as LA and San Diego stuff. The one I bought is from 2002, so I don't thik they come out with a new one every year.
Passporter is the best guide and they are working on one for DL to come out later this spring, I believe. The internet will be your best (and cheapest) bet! Good luck & have a great time!