I've just got my letter as well, and will be making my appointment on Monday.
Lisa, it is really important that you go, but HONESTLY it's not bad.
I can put my hand on my heart and say that I would rather have 10 smears rather than one trip to the dentist.
I'd even rather have a smear than go to the hairdresser!
Possibly TMI coming up:
It's much, much, much better if you can relax. If you tense up 'down there' it will be more uncomfortable. I know that's easier said than done, but it really will help.
When they do the sweep with the lolly stick, it feels odd - I don't think it's painful at all, but it's a very strange sensation. So don't be surprised.
If you want, take two ibuprofen about an hour before you go. (As long as you're not allergic etc etc).
Don't book it around your period. If the cells are 'contaminated' they'll just call you back and you'll have to have it done again. Mid cycle is a good time.
It's really not too bad, so please go for it. 
Rachel