Ok,
As im on a bargain hunt of late what with my Free AntiVirus thread, i thought i would start a free Firewall thread too.
I use Sygate Personal Firewall from
http://smb.sygate.com/products/spf_standard.htm which again is absolutely scott free for home users and is the best Firewall i have found so far for nowt.
I installed this and used Nortons own security scanner to test it - now it did find a couple of open ports, but i closed them easily from within the Firewall itself with the information gained from Norton, it simply meant the port wasnt closed by default.
You can find the Norton security scanner here -
http://security.symantec.com/default...d=ie&venid=sym
Let me know if you know of any better free firewalls.