Listen i have a couple of good books to list .

Phone boy wrote a book you can get it at www.bookpool.com go to the phoneboy web site and get the name also www.secinf.net has alot of great free ebooks on checkpoint and firewalls in general but the best firewall book for begginers is called building internet firewalls by oreilly press at www.oreilly.com ,another good book to read i would whole heartedly recomend is called active defense by sybex.com.

Hope that helps

EvIl