Hey Rick...I've been using IK Multimedia's Stealth Pedal and Amp sims (did a review a bit back) and have had really good luck with tone stuff. It's not a 'real amp' but at this point in my world, I want it to work and have found this to be very good.

I have a Mac which comes preloaded with Garageband which is a mighty nifty program and does quite a lot for being loaded as a free program. As needed, I would go up to Logic.

However, if you are a PC person, I've heard good things about Cubase (Steinberg). There's different levels to get in on so you don't have t spend a fortune to know if it will work.