How do you tell a guy that you just want to be friends?

[Queen X]

Ok, so there is this guy Im seeing at the place of work, and his job position deals with a lot of traveling from Nevada, New York, and Florida. Lately hes been out of state. In fact we dont live in the same state! We havent seen each other in a month or so. I thought it could work out but I was told before I that long distance relationships dont work out. And right now I can actually cosign that statement. And the reason is because for the longest time I have had a crush on this guy and I feel like if I dont make a move now it will be too late. The only thing is the guy Im with right now knows my big longtime crush. Enough to put each other on their top myspace page! What should I tell him? And should I tell him in person, or should I do it over the phone? Please help...