I'm 15, almost 16 and my dad wants to take me away from all my friends. My mom just died and I want to know if I can live with my stepdad.

I am sorry, no, your step dad has not legal standing what so ever. You dad takes over legal custody at the death of your mom. I am sorry for your loss and this move makes it worst.
How far away does he live?

You still have a voice though, Maybe your step dad should fight for custody. He's taken care of you right? As appose to your father? And you are old enough to speak and have a law guardian.