Is he starting to like me? He first asked my friend if i had a boyfriend, then he gave me the 'i wanna talk to you' look several times, then he sat behind me on the bus today and whenever i am around he tries to act cool.

Hey, I am pretty sure he likes you cause most guys tend to act cool around girls they like and the fact that he looks at you is another hint.  He may be the type of guy who wants the girl he likes to feel like his always caring and thinking of you.  Good luck, I hope this help :D and ... Go for it ;)