according to superantispyware's site the newest version of superantispyware v3.9 is compatible with vista
http://www.superantispyware.com/
and according to ewido's site avg anti-spyware v7.5 is compatible with vista
http://www.ewido.net/en/download/
and the new ad-aware 2007 is compatible with vista
http://www.download.com/Ad-Aware-200...html?tag=lst-1
and as r3drock3t88 posted spybot S&D is compatible with vista
all of the above scanners are good anti-spyware scanners and have free versions.