These are a number of short guides.
I wrote each assuming the reader to be completely new to the GIMP, so no experience is assumed.
Many of the tutorials also have an accompanying flash video.
These guides are a few years old, and a few of the menu locations might have changed -- but most details are still spot-on. The official GIMP site has some newer documentation which can be very good, but I do find that folks completely unfamiliar soemtimes have trouble following along. The tutorials here are short and quick and meant to bridge that little gap between those completely new to the GIMP and "newer" users that know how to get around the GIMP interface but want to learn to do many other things.
So, I hope these simple HOW-TOs help you out, and when you're ready:
GIMP official documentation