Hi 3rdstone, LePou who is a Canadian plugin maker has some good free amp sims. They are heads but he also has a convolver that is separate so you can load in Wav files of speaker Cab's. As far as I am aware the convolver is only avaiable for Mac users and I use Windows 7. Maybe one day!
The link above has a load of different Free Amps and Pedals and is certainly worth a look! It can't hurt as it is all free!!