A computer radio has digital circuits that allow you to customize the way the radio works. How far the servos move, end point adjustments, the ability to mix two channels so they work together, etc.
Here's a kind of typical one:
http://www2.towerhobbies.com/cgi-bin...I=LXGAF1**&P=0
The tech data explains some of the things it does.
I tend to disagree that you, as a beginner, want a computer radio. There's enough to deal with as it is. A basic radio, a simple 2 meter wingspan sailplane, and a high-start is how I learned to fly RC. It's still lots of fun because it's just you and the wind and the thermals, trying to get in good flights. It will teach you how to
fly, not just how to push buttons.
For instance, North East Sailplane is a good outfit and here's exactly what I've described in a complete package for not a lot of $$:
http://www.nesail.com/detail.php?productID=1445