You can find a big list of scum programs here: http://www.spywareguide.com/product_list_full.php
You can learn all about spyware here:
http://www.spywareguide.com/txt_detect.php
You can download this program for free, it uninstalls the major culprits completely: http://www.lavasoft.de/software/adaware/
This program is even more sophisticated:
http://spybot.safer-networking.de/index.php?lang=en&page=news
If you use Gator, download roboform for free. It will transfer all your Gator info to itself, then you can get rid of Gator with one of the previous program. You CANNOT delete gator on your own, it leaves a small program behind that slowly downloads from gator again until you have the full spyware back on your computer.
Roboform: http://www.roboform.com/
If you use Kaza or similair program to download music, replace it with Diet Kaza. Same thing, no scum! http://www.dietk.com/