I had PF severely. It totally sucked! I went to my pcp for the problem. Now, this sounds bizarre, and guess it is, but he told me to get athletic tape and place it the length of my arch. I also wrapped a piece around my foot to keep it in place. IT WORKED! I was sceptical, but really willing to try anything at that point. He said he did not know why, but that was the most effective way he found of treating PF. I also lost about ten lbs at the same time, so I'm sure that was a factor. I did that for about a month and you know it never did come back.
Good luck!