Norton products for Tiger: complete re- or uninstall?

I have used Norton AntiVirus and Personal Firewall on my PowerBook with OS 10.3 Panther for the past year since I bought my computer. I know some people think they are not necessary, but since I had moved from Windows, at the time I thought they were essential.
I also had OSX's built in firewall turned on and am behind a router. I think that was an extremely "safe" setup.
However, I upgraded to 10.4.5 Tiger about 2 weeks week ago (mostly for Spotlight, better .Mac integration and some useful widgets), which seems to be incompatible with the Nortons. At least I got error messages as they could not load up some extensions or something. I trashed the Norton folders immediately found in the Applications folder to temporarily solve the issue.
Now my questions are:
1.) If there is a way to reinstall both Norton software, maybe with an update for Tiger - is there any?
2.) If there is no way to get them work with Tiger, how do I completely uninstall them? I suspect there would be lots of other files installed with Norton that are not in the Applications folder, thus I did not trash them.
3.) I moved to S.Korea for a year from the US recently, and have extremely fast broadband access here, however we are all required in my building to run antivirus software on our computers regardless of operating system - I guess to prevent infecting others on the network. Now, if I do not have Norton, what other software should I use??

Thank you in advance!