Suggest a good free firewall

[NiteFox]

Nice, innit? Since I purchased my DS back at the launch in March, it's been a faithful gaming friend, and the upcoming slew of online games makes me very excited The thought of dispensing red shells to schmucks across the seas in Mario Kart DS makes me giddy like a little schoolgirl.

Being a perennial cheapskate, and also lacking a good other reason for buying a wireless router, I purchase the WiFi dongle for a shade less than thirty quid. It works perfectly, but with one slight snafu.

ZoneAlarm Free. It doesn't like the dongle, and the dongle doesn't like it. To even get connected I have to turn off ZoneAlarm even after giving a zillion and one permissions to various IP addresses and programs connected to the WiFi service. The problem is that all potential fixes involve allowing access to certain ports, which ZoneAlarm Free doesn't allow. I don't like running around without a firewall, and I did try disabling ZA and replacing it with Windows Firewall, which worked for my DS, but I'm not sure worked at all for anything else since it happily allowed Firefox to access the Internet even though I hadn't granted permission to said program in WF :ph34r:

Being a cheapskate, I don't want to drop hard cash on a firewall, so I'm looking for a better free alternative to ZA that will allow eldritch port magickry.

I'm also familiar with the software-finding skills that the Lounge has. DeeBye, I'm looking at you.