WOW... you're in troubles....Neh, don't worry.... first of all, calm down, then....there's not a good idea to try to tell him just like that...try to talk about the homosexuality in indirect form, I don't have that trouble because I came out A LONG time ago, but, it's really hard to make understand some str8 guys that you think they are great person and like them.... If you can get some information about what he thinks about the gay guys, you can try to come out with him, but make sure that he will not misunderstanding.... It's a bad idea to not try to make them feel comfortable, maybe even if you like him, it's better to first let him ow that you like the guys in general not especificly him....
Good Luck man....