Help finding good bike fitter

http://www.slowtwitch.com/fitters/

You should ask lots of questions about

what their fitting philosophy is?
what certifications do they have (if any)?
what system they use?
how long they've been doing it?
what kind of shop is it?
how long is the fitting going to take?
can you get a report of the measurements?
what measurements will they take?
can you come in for adjustments if you need it?
are they nice or impatient?
what does the fit studio look like (if it's just done on the floor of the store that's not good enough)

The key is if you're going to spend the money you should get your value and make sure you're not getting a "bike sizing". A fit should be more comprehensive and you should also be prepared to spend some money on a stem, seatpost, or misc to make the fit right.

In some ways, to me, it's like finding a contractor. You can't have any guarantee the work will be done right but you can ask questions to get comfortable and give you a better chance of success.

My $.02

What if they have no "certifications" and don't use any particular system?  Does that make someone any less qualified?

While FIST is a great system to use (and there are others), there is also quite a bit of intuitive aspects and experience that make a bigger difference and are more valuable in my opinion.  I'll take the guy with 20 years in the shop who throws you on a trainer and eyeballs and make adjustments accordingly over the college kid who went to a FIST certification, uses a computer and has only been doing for 6 months every day of the week.

But yes - those are good questions to ask.  I'd personally find people who have used the place for fitting and ask THEM how their fit went.

I have had 4 different fits. First three were very different last two were with same guy. I trust him now so if I wanted a new bike, I'd discuss it with him and trust him to tell me which one is better fit for me and order it without riding it. He can set up a bike so it feel like all my other bikes or similar out the door.

Other things to consider:
Cost?
Refunded towards a new bike? if so time limit? Does it depend on cost of bike?
Philosophy? A big place here in MA fits most folks doing tris similarly even though we are different with different issues
Follow up? included in fee? what time frame?
What happens if you have multiple bikes? fee cost all or one bike?

I agree personal recommendation is best from multiple folks.