I'm new here and viewing this thread has prompted me to pass on some info about my own (long) experience with plantar fasciitis. Hopefully, at least, it'll be a bit interesting, even better if it actually helps (APE & Chicken especially). Sorry if it's a bit wordy, reading it is not compulsory. I also acknowledge that I am reiterating what some others have mentioned.

I've had it (PF), in varying degrees, for longer than I can remember, certainly at least 3 years. I tried resting (in desperation, for 3 months), that didn't work. Neither has: physio, cross frictions, calf stretching, changing shoes, golf balls, tennis balls, wooden roller thing, and a few more I can't (or choose not to) remember. Although I never succumbed to the needle.
Until recently, the one thing that gave me almost instant relief was an arch-supporting orthotic. Do I recommend that route? No. Why? Because it stopped the pf but caused other problems: my ankles didn't feel 'right', eventually leading to ankle pain especially if I didn't put my orthotics in every pair of shoes I wore. But, more importantly, it's a remedy, a prop, or a mask — like taking aspirin for a headache caused by stress.
What made my pf worse was wearing flat shoes or sandals. That's no surprise, because that's what most people say will happen.
Yet, there was a clue, and Hopey (post no. 7), is right on the money.

I'd noticed, quite recently that running long distances in my Inov8s Terrocs (not much cushioning or support there) didn't make things any worse; if anything, it was slightly better. So, to cut a long story just a little bit shorter, I started to read about alternatives (ideas that seemed diametrically opposed to conventional wisdom) and subsequently found a nice hard road, dumped the shoes and socks, and went for a 2 mile run.
The results? Well, some blisters of course, but almost immediately, and certainly within a few days (and a little more daft running), miraculous reduction in PF symptoms. Some 5 weeks later with about 5% of my running being done barefoot, the improvement continues.
I now spend as much time as possible out of shoes. My barefoot running is minimal (you can't do much early on), but the new found strength already apparent in my feet seems to be doing the trick.

The answer (for me anyway) was in the feet. Don't shield them or protect them, get them working, let them feel the ground you stamp on, and they'll show you how to stamp no more. But do take it easy.

And if it doesn't work? Then you can try the bat's wee.