He only texts me!! What does this mean?

I met this guy a few months ago (about 2 months ago) and we have literally talked everyday since we met. He is about 25 and I am finishing up at university. We haven't been out on a date because we live in different cities and since I am still in college it is hard to get away. My question is, he always texts me and we chat on instant message, but he has only called me once when he was drunk. Like I said we talk multiple times a day everyday, sometimes for hours at a time, but is it a mad sign that he doesn't call me? Its really unlikely that he has a girlfriend, he has mentioned his ex before.

Also, we have now known each other for over 2 months and we have never been on a date... How long before I turn into an internet pen pal as opposed to a love interest?

Oh,I'm silly I should have said this before, he asks me pretty constantly to come and visit him! We have made plans to visit each other as soon as I am done with school.