Si, esistono le versioni a pagamento e una free:
http://www.download.com/ZoneAlarm/3003-10435_4-10421033.html ?tag=lst-0-4
I migliori firewall secondo me sono:
Sygate Personal Firewall:
ftp://ftp.forthnet.gr/pub/simtelnet/win95/secsys/spf.exe
Kerio Personal Firewall:
http://download.vnunet.it/download/374.html
Outpost Firewall:
http://www.agnitum.com/download/outpostfree.html