I have a stack of books that i am reading at the moment, I also have a hypnobirthing book and CD that you could burn that should help you with that fear... Its not the full course, but it helped me first time around knowing that my body really knew what it was doing.

I read in one of them the other day (think it was Ina Mays book) that both a penis and a tampon 'fit' at the time that it is required too, but both can hurt if you are anxious and stressed about it - consider the size difference ... labour is all about your body getting ready to birth your baby and if you do it right, the baby will fit

Anyway, more than happy to lend them to you