Boy problems (real boys, not the ones I look after)

I went out on a 'date' last Thursday with a guy named Bob. We've hung out before and for me he's just a friend. I think he wants more of a relationship but I don't. On Saturday night I'm supposed to go out on a real date with a guy named Tom. I could see myself dating Tom. Bob and Tom are friends and hang out with the same group of guys that I hang out with. This situation seems like it's going to become pretty sticky. Bob texted me tonight asking if I want to go the see the Pirates movie tomorrow but I'm already going with Tom on Saturday. I didn't mention that to Bob. SOOOO....now I'm stuck and this is exactly what I don't want to be stuck in.