yoni is correct, this is actually spyware so you'll need to scan your system using both a virus scanner and spyware programs.
Spyware can be removed using Adaware SE and Spybot S&D
If you need a virus scanner you can get free versions for temp. use from these companies.
http://www.avast.com/ - Free to home users
http://esd.element5.com/demoreg.html...2&languageid=1 - Microsoft users can get a 6 month free trial of F-Secure from this link.