Be careful when downloading any software to your system, as any application could be hiding spyware or adware. Whenever you see a terms of service or license agreement, read it. Just clicking "OK" means you might miss important details that will affect you or your computer.
Build a barrier 
Special report
Spyware epidemic
Install a personal firewall application such as ZoneLabs' ZoneAlarm on your PC. It's designed to block software programs from communicating with the Internet without permission and should tell you when software on your system is trying to send out data.
Zap intruders
It often takes more than just removing the host program to delete the spyware and adware that it hid. Use an adware-detecting program such as Ad-Aware or Spybot-Search & Destroy to scan your computer for programs you're not aware of. Find out what the programs are and what they do before deleting them. But be careful--if you eliminate all adware programs, it can cause some associated software, such as the Kazaa file-sharing tool, to stop functioning.
CNET review:
Three ad-blocking apps
CNET Download:
When adware attacks
