im using Tiny Personal Firewall
for me, it is easier than ZoneAlarm

but you have to pay for it

im running two software firewalls with a hardware one at the sametime
router has one in it
act as a port blocker and minimal screening

the PC-Cillin 2003 anti-virus software has its software firewall as well and it isnt bad!

so far, ive been using voice and video just fine