I have always considered a Pap Smear as one of the less horrible tests as the "hole" is already there! (lol) No needles, cutting or stitches required.
Especially when you compare it to some of the horrible tests & procedures to do with BC (needle / core biopsy, CT scan, dye into the lymph glands, surgery etc).
BUT! I have a phobia to needles and I have heard it all - "But it's so fast"..."just don't look"..."Just think about something else"...Ha! Impossible. And I envy those who can go and get the needle / blood test like it's just part of the day, a mild annoyance at most. For me, it's a major stressful production. I called and hung up on the radiology clinic 4 times before actually getting up the nerve to book in for my aspiration (when they thought my cancer was just a cyst). I totally get the fear.
All I can offer is to DEFINATELY go to a place that specialises in them, ie. women's health clinic / family planning, so you know it will be over and done with fast. Also, let them know if you want them to explain anything, or NOT explain it - I find if I know too much about what's going on, it freaks me out more.
Maybe let them know when you are making the booking that you're nervous / terrified, so they can be prepared. Also, have you considered maybe taking a Ativan / Valium (or even Rescue Remedy) before going in? It may help, my GP has prescribed me both if I ever need them.
Rewarding / bribing yourself might help too, and the suggestion of getting someone to take you so you don't back out is great.
Best of luck with it, thankfully it's something we don't have to do that often!