I was once in a similar situation, and this may not mean much coming from a 13 year old, but the advice I can give is BE CAREFUL. Friendships are easy to ruin with love.
Ok... you need to take a step back on this one. Write him a letter,but don't say its you- post it anonymous & see what his reaction is..?
Hmm well you have to choose between your best friend you're in love with or just one of your friends. If I were you I would choose the one who I have feelings for and is my best friend. If your friend gets mad at you for that then they aren't a very good friend anyway.
Good point skateboy..!
Well if you want to be with him in a relationship then thats the risk you take. Tell him your feelings and just talk it over with him. The best thing you could do is tell him before you lose him. Also ask him what he think will happen if you and him don't work out in the future. Ask him if he thinks it will ruin your friendship or even if it doesn't work out will you and him still be able to continue being friends.