Use a remote foot pedal with a MacBook for stop and start?

Is there any way to hook up a foot pedal that when clicked on stage would
respond as if I was hitting the space bar on my Mac Book when preforming
live with Q-Midi (to start and stop within the live set)?

QMidi start and stop can be driven by MIDI events. Check the "Midi Transport" section in the Audio/MIDI settings:

Tim I don't use midi at all so if it's any help I figured out a neat way of doing this with an old Mac keyboard from around 2000 which is a full keyboard plus the section with the curser arrows and also then the number section. (although any old keyboard would do) and using a program called Quickeys. It looks a bit mad with this keyboard on the floor but I took all the keys off I didn't need and left 7 on the keyboard with enough space to hit with my foot. Those do all the things in this quickeys settings pic. I took the space bar off and use the 'M' key to start and stop QMidi as I found I was hitting the space bar unintentionally. Works great on my Macbook Pro anyhow.