Atariboy and Geeklimit.com have some good tips on removing Spyware and other mal-ware.
As an iT Geek, I quite often get asked to look at peoples machines outside work. The majority of the faults are related to spyware or virus activity making the PC slow, flaky or just unusable.
As each machine has a different configuration, a different set of software (usually) and often a different connection method to the internet, I have come to rely on ridding the PCs of some of the viruses and spyware by hand.
“Why?” I hear you cry. “When there all all those great, free utilities such as Ad-Aware and AVG?”.