M.S.
Like many others, I would recommend going to a high end running store (Luke's Locker, Run On) for a fitting. You don't have to buy there but the experience is worth the extra few $'s you will pay there versus Academy or Sports Authority. Luke's and Run On are also more likely to have Wide sizes available in the store versus having to special order/order online.
I've found that Saucony makes the widest shoes, but prefer Asics because they are narrower in the heel and feel better on my feet.