Our BM 3.8 budget is getting approved! Anyways, I requested $500 for
training. What would be our best source of self-training... we would
prefer that our other two admins could go through the training as well as
myself, so a book or some sort of self-teaching would be good.

Does anyone have any suggestions?

The part that really confuses me, specifically, is the packet filters
thing, and I think we really want to understand that part before we start
messing with them on our live network.