Amano

Here's my situation.

I've gone on three *very* successful dates with a girl who lives about 70 minutes away. At the end of our third date, we had "the talk" where we decided that the distance, although annoying, wasn't going to prevent us from continuing to date. I have two things i'd like advice on:

First, a more general question. How do I move from calling only to schedule or confirm a date, to calling more often to just talk with her? We always have wonderful conversations when we're out together, or when we're on the phone, but our phone calls so far have always had some purpose, like to schedule or confirm something, and just "happened" to have other conversation as well. How do I move from that to calling just for the sake of talking to her?

Second, a more specific/situational question. I called her Sunday late evening, (we had gone out the Saturday evening before), but it was a bad time (big paper due that Monday she hadn't started on), and she couldn't talk for long. We ended the conversation on the note that the next evening, she'd be pretty free the rest of the week to call. It's late Tuesday evening (two days after she said she'd call), and she hasnt called since. How long do I wait before I call her? Or do I not call her again at all? This would be the first time where she has to make the decision to call, because all other phone coversations have been either from me calling, or her directly returning a missed call (I don't know if that makes any sense).

I find it hard to believe that she would all of a sudden not be interested in me anymore. She's given me tons of signals whenever we're out, along with just coming out and saying multiple times that she really likes me. Yet, I still get paranoid. :-(

Any ideas?