Oooh - I love mine!
I have two tats: 1 lower back and 1 center back - see here:
http://farm1.static.flickr.com/109/2...fafafc1f_o.jpg
Both hurt when I got them. I am pretty sure that is a universal part of the experience. The pain level will vary based on what type of design you choose. My peacock feathers involved a lot of detailed line work, then coloring, then white line work, so they were a lot more painful than my moon-ankh.
When the artist first started working it was a very sharp intense pain like being cut or stung by a bee. Once he had been working for a few minutes it subsided to a steady pain - not comfortable, but not terrible. I was able to sit still the entire time without jerking, but another person there was having more trouble with staying still for his.
I closed my eyes and concentrated on the vibrations from the needle and just let myself zone out and breathe evenly.
On a personal scale of pain, 1 being a stubbed toe/broken nail and 10 being broken ribs...I would say the line work on my lower back tattoo was a 5 (somewhat like a continuous shot or having salt water on a burn) and the coloring was a 3. My mid-back was about 1 less on both parts.
Have you found your artist yet? I definitely suggest looking around and seeing different people's work and have something custom designed or design your own. Both of mine are custom and I love them :)