There's an offer from
McAfee,
25% Off McAfee VirusScan Plus for 3 PCs
Only $44.99 after Coupon Code! Reg: $59.99
Coupon Code: MC0811313756pC727241137
Personally I don't use any antivirus although maybe I should start, since Mac viruses are starting to increase in volume ¬.¬
Otherwise I use Northon on my windows machines.