Right, here's a few to sort you out - I have used them and still use em myself - good programmes! And they were recommended by professional geeks too

First, is a pretty powerfull online scanner - worked well for me! Bonus to this one over the others is you only have to visti the web addy and run it, no download or install needed - http://www.ewido.net/en/onlinescan/

Next, some "local" spyware removers;

Spybot - Search and Destroy
Ad Aware Personal SE

Next, some good programmes for monitoring spyware before it comes into your PC. Prevention is always better for cure and these two work like real-time antivirus programmes, except the only monitor and block spyware;

SpywareBlaster 3.4
SpywareGuard 2.2

After that - firewalls! Windows XP standard firewall is shite, so you need another one. Best two freeware ones are ZoneAlarm ( http://soho.sygate.com/products/spf_standard.htm ) which is very good, but on some systems can slow your PC down a little. If this happens, then your best off using Sygate Personal Firewall ( http://soho.sygate.com/products/spf_standard.htm ) which is also highly rated.

For freeware Anti Virus best bet is Grisoft's AVG - http://www.grisoft.com/doc/40/lng/ww

HTH's