Pedal to change Live Guitar effects

Not with the GB amps. But there may be some 3rd party software that would allow that.

Try this. Put one set of effects on one channel (clean) and another set of effects on the other (distorted). See if using the arrow keys will change between the two. If so, you can cannibalize an old two button mouse to use as a footswitch and a macro utility like iKeys to assign arrow key to the appropriate button.

However, I would recommend looking into this product rather than trying to adapt GarageBand.

See if using the arrow keys will change between the two.

They would.

I'd really like to have more than two preset effects

You could set up as many "effect" tracks as you want, the only trick is switching between them on-the-fly.

do you know if you can set up a foot controller for GT Player Express?

According to the manual (see M-Audio Support), the GT Player rack is controled by MIDI with its own software to assign the switching accordingly. So theoretically, the following hardware should do what you want...

JamLab for Guitar to USB plus FX Rack software
Behringer Midi Foot Controller
Uno Midi to USB (for Behringer)

Native Instruments GuitarRig is an amp and effects emulation package that comes with its own dedicated foot controller for changing its presets and effects. I think it can be had for around $300 but you need a fast Mac to run the effects.

IK Multimedia Amplitube and Amplitube Live are less expensive software amp and effects that can be controlled by a third-party MIDI foot controller such as the Behringer recommended above.

There are more of these kinds of products coming to market all the time--but they all require quite a bit of processing power, especially if you are going to run one of them and GarageBand at the same time.

As good as the computer amp and effect models are getting these days, I'm beginning to conclude that I would be better off running my guitar into a Line 6 PodXT dedicated stand-alone effects box, and taking the output from that into GarageBand. And there are many competing guitar effects boxes besides the Pod that would work also.

Having an external effects box means no additional processing load on your computer. It also means you have something you can take to a gig and plug into an amp, without needing a computer rig to play your guitar in front of people.

Wheat, I used to have the POD (not the XT model) and wasn't completely happy with it so I sold it. Since starting to use GB, I wish I still had it sometimes. Still, I think I'd prefer to get my basic guitar tone from it, then add effects in GB, so I can change my mind if I choose to. I think the amp sims put a lot more tax on the CPU than basic effects like reverb. At least that's been my experience.

Thanks for the clarification on this, Wheat. I thought it could be done, but not sure the RAMifications and the better alternatives.

Will be nice to know. Once the INTEL laptops arrive on the scene, this would be a good use for musicians who travel light but play heavy. 😉