1st step; searching for stuff that 'gets rid of spyware' is the FIRST place that spyware is hidden. You have to ask around and find out who uses what predominantly.
Download.com is a safe bet as most of there stuff is certified safe; though the liability will never be on them if it isn't.
Adaware SE is a good start as it is free and works well. It has options to upgrade but it isn't required.
http://www.download.com/3000-2144-10045910.html
Hijack this is good if you know what you're looking for; it'll kill processes that start up on the machine.
http://www.download.com/Trend-Micro-HijackThis/3000-8022_4-10379544.html?tag=lst-1
Spybot is still the free-est and equally efficient spyware killer.
http://www.download.com/3000-2144-10122137.html
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Don't forget adaware personal edition and hijack this. Both are free and very efficient at getting things that Spybot doesn't get; the reverse is true if you have adaware but not spybot.
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