Here is the list of antiviruses that support 64bit platform:-
AVG (but not Free AVG)
eTrust 7.1 (CA)
McAfee Enterprise 8.x
Symantec Corp (10.1?)
Kindly tell me if I miss something.
Being a Microsoft MVP I am always thrilled by the Microsoft technologies.Windows XP is a real life time experience.It's a joy,it's an adventure to nurture with this operating system.My blog has been dedicated to this great opearting system