What I do that never fails... maybe because mine are little piggies...
I put the pill in a small piece of soft cheese and have a second small 'backup' piece. Then I make sure they see BOTH pieces. They are so eager to get to that second treat that they gobble the first one right up without spitting out the pill!
Mine don't often get people food so they get all excited for their treat! I always have to have extra cheese on hand so that the other kids get some to!