Is it one of your front teeth or the big molars? If it's a front one then there is only one root, but a rear one can have three or four. Check this site out, it's extremely informative:
http://www.animated-teeth.com/../index.htm
I had root canal treatment last year on one of my crowned front teeth. It had to be done as an abcess had appeared. The crown was undamaged even with this work, but a few months later it started to work loose (not just coming unstuck) and a new crown had to be made. A nice job was done too of it!
The only thing I didn't like about the canal treatment was the adrenalin injections to stop the bleeding - they hurt - a lot shall we say!
As you say it has to be done, sooner rather than later. I love hearing about other peoples dental experiences, fascinating stuff!