Mark,
I found the PrepCast Simulator to be an excellent preparation tool for the real exam. I though the questions in the test bank to be either spot-on or slightly harder in some instances than what I experienced during the PMI exam back in October.
Try to relax and just let it flow for the exam. There are exam-taking hints throughout the boards and the web, some more useful than others. The ones that I found most useful were things like "read the last sentence of the question first" and "eliminate obviously wrong answers." I found that on the PMI exam, there was at least one, and sometimes two clearly wrong choices on each question. Only a few were of the type of "pick the rightest of these four right answers."
Relax and just let it happen. Good luck!
H