Hi.
The NETBios requests you speak of are actually not all that much of a problem - this is good old Microsoft coming up with a blinder again. A NETbios thingy is basically the name of your computer in non-IP address terms - if you have a small home network you'd probably refer to your computers as "Living Room Machine" or Windows 98 Machine", instead of 192.168.*.*, and all this is is a request for who you are. Now this could be used maliciously, but in general it's just another Microsoft Networked machine having a chat. I would still be worried however, cos the best way to be safe from attack is not to be seen - hence blocking these NETBios requests is a good way of being invisible. A Cling-On cloak isthe order of the day.
I agree with the other posters in this thread -
www.grc.com is excellent and where I learnt alot about internet security, and indeed possibly the best of all the firewall stuff Zonealarm.
Have fun.