What to do about this guy?

ok im in yr 8 and I really like this guy he is one of me best mates we are in the same yr sit on the same desk and he is one of my best friends what can i do he has a girl friend they havnt been going out for long but he doent like her she just looked nice for like on day and she is now back to her normal self witch aint so great she is one of my friends not one of my best but is a friend. I really like this guy i have for a while what can I do any ideas i dont want to hurt anyone and i fink he knows i like him !