In reply to Guy Millar:
It's worth considering:
a) Joining a club
b) Finding partners on here who are willing to help
c) Reading all the books you can lay your hands on, getting the kit and practicing at a local crag at low height until you know the systems and then just doing it - it's not REALLY that hard...
d) if you still don't feel confident hire an instructor, or hire an instructor anyway who will be able to tailor a session specifically to you. If you already know the knots, how to clip an extender, roughly how you place protection, a few techniques for building an anchor etc. they will be able to accelerate the course drastically so you get more out of it. General courses are OK but often you cover ground which you may already know plenty about...
I would offer to help, but I'm so snowed under with work at the moment it would be too difficult to find the time... what part of Somerset are you in?