Everyone I know who has already take the exam (and passed) did the Laura Gasparis DVDs and some kind of prep book with practice exams. Some used Pass CCRN! and some used Kaplan. I take the exam tomorrow, and I have done the Gasparis DVDs, Kaplan book, and Cammy Fancher's podcasts. Also, if your hospital uses CE Direct for CEUs, then you should have access to CCRN study material (in PP or PDF form).
I don't know anyone who has gone to an actual class to prep for the CCRN, and all but one person has passed on the first attempt. The most common advice I have received is to do LOTS of practice questions. It really helps to familiarize yourself with the test format and identify problem areas.
Good luck! (I take it tomorrow:-/)