Hey CrazyCat,
I'll tell you what seems to have done ok for me.
The short version is: the next time you talk or see him, ease into the topic. Test the waters before you Explain your feelings.
Basically, if you feel this way, you need to be honest about your feelings. Don't Be ashamed of them. But I wouldn't recommend jumping into it; We're not going for shock value. (;
Make sure he's comfortable talking about the topic of relationships, and then ease your way into explaining how you feel. Be certain that he'll hear you through, and be sincere.
Cheers, CrazyCat. Hope this helped in any way, and I hope all goes well. If I ended making myself sound like an idiot I can flesh this out a little more :p