Free alternative to other anti-spyware apps

Malwarebytes' Anti-Malware detects and cleans malicious software like no other. It's my first string of defense when a computer is infected with something nasty like some of the recent hoax anti-virus apps that have been plaguing people lately. The free version does not have realtime protection, so you will have to run the scans manually.  However, you can have realtime protection after a one-time payment of $24.95.

http://www.malwarebytes.org/mbam.php