A lot of people really struggled, but I took the simple approach. I studied for one week, I read the 2003 book twice (I can't stand lots of reading on computer screens). The first time through I highlighted what I believed could possibly be included on the exam (at least 1/4 the book is totally not going to show up, like all the stuff on fines), and the second time I read only the highlighted sections.
Other than that I read the law quizzes from the University of Washington law class website (click the link below and then click the Pharm 543 link and find the quiz answers).
Between that and working in pharmacies there I had no problem, though many people seem to have trouble, so just try not to second guess yourself, and know the DEA 222 forms by color (which color goes to who).
I never found a good link that went over updated/new laws, but I still passed fine (and I haven't even lived in state for the past year).