For Norton AV, I found that, while the uninstaller on the disk did not work, the one on the Norton website did work for me.
Here is a link to that.
Just a little addendum to what the others said. In general, it is sufficient to uninstall by dragging the application folder to the trash. When applications install using the installer program (they install by an executable program file that has an icon that looks like a hard disk with an arrow over it), then sometimes this same installer package can be used to uninstall the program -- if you run it again, it will have an uninstall or options button on the lower left. This is mostly an issue with programs that modify some aspect of system function by running in the background (dasher, sidetrack), or act as plugins to other programs (pithhelmet, httpmail, etc).
I only sort of agree that this aspect of OS X is better than it is on Windows.... For many programs, where dragging to the trash is sufficient, it's great. For programs where dragging to the trash is not sufficient, I find the OS X system confusing, because there is no central add/remove software to go to as in control panel to systematically remove these.
Also, hopefully it will not be an issue, but please note that when you uninstall a program by dragging it to the trash, you DO NOT delete its preferences, in almost every case. This is usually not a problem -- they'll be there for you if you want to use the program again later. But since these preferences and support files corrupting is often a cause of program crashes in both Windows and OS X, for OS X apps, in general, dragging the app to the trash and then re-installing it won't resolve this kind of issue.
But for the most part, like the others said, you drag to the trash and you don't have to worry about it.
