I think you should leave your friend alone- this isnt what he wants- or if it is, let him suggest it-- you have already intimated that you are interest and it doesnt sound like he wants to be in a same sex relationship. What you should do is go to the college's gay and lesbian center-or something in your city that is open and affirming to people who are gay or bisexual. You need to be around other men who desire men so that you can explore your sexual feelings ina supportive environment. If you keep approaching your friend he might eventually feel pushed and threatened and end your relationship and you don't want that to happen. Learn more about yourself on the web as well- Lambda ( a gay legal organization) and the National Gay and Lesbian Task Force ( social and civil issues) are among the many organizations you can find on the web. Locally, I bet there are mixers, dances, bars etc where you can meet men.
Bottom line- go where you can have success and acceptance and do not pressure your friend. He can't change his orientation just for you- its sad foryou that you have a crush on someone who is most likely unattainable, but get over it and find someone who wants you just as much as you want him. If you have these thoughts they are real and there is nothing wrong with them. Society is getting more and more knowledgable and accepting about homosexuality. Explore yourself and enjoy your self-whatever your sexual orientation may be.
Considering that your friend is straight, I don't think it's wise to keep bringing up your sexual feelings for him, especially if he's uncomfortable with homosexuality. Its important to remember that your field of opportunity is limited to people in the same situation as you and it's not really fair to try to push homosexuality on anyone. If he's happy with himself and his sexual preference I think you need to accept that and if it's hard to keep your friendship without the frustration you feel then you owe it to yourself to move on from the situation. But that's just my opinion.