Guy I like and want to ask out is studying abroad...?

My first post here, I'm a total newb, but I'm desperate for help.

I started an internship in Boston this July and met the most charming, funny guy. I had a boyfriend at the time (who I've since broken up with), so there was some flirting and a couple lunch outings (as coworkers), but nothing actually definitive. The guy left to study abroad in Spain in August. We keep in touch on Facebook and have im-ed a few times. He gets back to Boston in early December, and then heads off to school in New York in January (but lives near Boston). I go to school in Boston. So it's kind of a weird long-distance during the school year type thing if it were to ever happen.

But I haven't been able to stop thinking about him for months. Should I ask him out over Facebook? Or is that a total faux pas? I really, really want to and I don't know of any reason he would reject me, unless he likes someone else or I'm just friend-zoned or something.

How about this....around the time he gets back to Boston, pick up the phone and call him. Yes do ask him out for coffee or lunch to catch up. You are in a position that guys usually go through...now you know what it's like to be the asker and not the askee. Just think of all the times you were flattered when a guy plucked up the courage to ask you out. I'm sure he will be flattered that you did.

Haha I've never actually been asked out. I've dated one guy and asked him out...

Wow really?