Why doesn't he reply or call?

So, of course I have pretty much fallen for this guy pretty deeply. ALL of the signs point to YES he truly (at least) likes me, I've been told by a few of my friends that he does like me most definitely. He has my e-mail and he had been e-mailing me frequently (PARAGRAPHS long). Recently, I tactfully gave him my phone number, it wasn't out of desperation either and now he hasn't e-mailed or called. He said that he would and asked me not to worry when he didn't reply. No, he doesn't have a girlfriend. Yes, he is shy. I know I can't show you the entire situation because this is online, so you can't totally experience it. But some tips and advice would be nice. I'm currently trying to be patient and wait things out for him to work up some courage to call - possibly. But it is KILLING me that he isn't calling and/or replying to me yet. T_T