In reply to chris fox:
Bike shops around here have a pitiful selection of shoes in my size to try on, so I've tended to buy a few pairs from somewhere like CRC or Wiggle and send back the ones that don't fit - free returns.
What are you wearing at the moment? Sounds like you need something with a wider fit - Shimano and Sidi can be ordered in wide, NorthWave come up quite wide. I was surprised how wide Diadora and Gaerne are, considering they're Italian.