yeah, what he said... as long as you've got some kind of multieffects, or really anything with an amp modeler, then you can plug into the effects return.

I personnally don't like the sound of two guitars into one amp, but that may have been due to the fact that I was playing an electric through an acoustic amp with this other guy who was also playing electric... sounds much better with 2 amps, but you do what you gotta do to get the job done.