Originally posted by Maxx:
Does anybody know if there is a way to hook an electric guitar to a Mac, have it manipulate the sound and send the output to an amp, all in real time ?
Yes...but there will always be latency (time from when you play the note to when you hear it). With a good setup, you can get the latency down to 1-2 milleseconds, which might be acceptable. If you don't have a powerful computer and a good sound card (not the built-in one) then you'll have more like 22 milleseconds, which would be a drag.
So, yes, you can do it. You can use a program like Cubase (www.steinberg.net), which is intended to use effects for recording...there are other programs that would work...but for some people even 1-2 milleseconds is too long.