Silver, I believe I've got it. Check this out:
-I took a sprite and attached two platform objects to it.
-For the first platform object I set the "Control" name as "Player 1". For the second platform object I set the "Control" name as "Player 2".
-I then went into the Properties menu and went to the "Controls" sub menu and set the controls for Arrows keys for Player 1 (P1), and then set the controls for WASD for Player 2 (P2).
-I then created a Global variable called "Controls"
-I then went into the event sheet and created the following events in order to test it:
.Cap = https://rapidshare.com/files/3520367228/WASD-Arrow%20Movement.cap
Press '0' for Arrow control. Press '1' for WASD control (I only put W, A, and D in, you can fill in the rest with what you need).