On-line Guides: First I'll give a brief survey of some of the online fitting guides. At top right is a chart detailing the topics covered by these sites:
Rivendell Bikes has a nice online guide for choosing a bike. This is predominantly a guide for choosing a frame size, based predominantly on pubic bone height (AKA "inseam"). It has an interesting rule for how to determine the leaning angle of the torso. This is oriented towards comfort and not racing sizing (which really is not addressed by any of these sites.)
Bikerowave (love the name) has a pretty plainly presented (looks like a forum entry) discussion, but the information there is good.
Jim Langley's excellent site has made the posts of this blog before. He presents fitting as a troubleshooting guide. Good if the bike you already own falls within the range of what you need, not so useful as a buyer's guide. (Langley quotes from Ivan Illich -- hm, good topic in itself for some future post.)
Kirby Palm's long discourse on bike fitting is encyclopedic. Anyone who can write this much on a topic probably knows something about his subject. If not, let's hope he gets lucky. Seriously, this is arranged in a somewhat wordy narrative, but is quite comprehensive and useful.
Wabicycles has a frame-spec focused site that is oriented toward fixies. It information is compactly organized and not unsophisticated. Definitely the place to go if you're thinking about converting that old Raleigh from the '70s into a fixie.
Bike Fit Kit: The "Fit Kit" sold to cycle shops to determine bicycle fit. Since they sell the kits, they don't "give away" their methods online, but visiting their site is interesting in what it says about their approach.
The Fitmaster is the all-in-one fitting machine seen in many bike shops. Shops in at least 25 states in the US have these. A nice, integrated system combined with training on how to use it. This is a good investment for any bike shop, it would seem.
Ride Boutique is certified on several different fitting systems. If you live near Ann Arbor and have a couple of Benjamins to spare, this might be time (oh, yes, and money) well spent.
Papa Wheelie's bicycle shops (again, I love that name) in Boston and Portsmouth, NH also has advanced fitting services. They mention the magic word, "chondromalacia," which I suffer from.
Bicycle fitting services in Tampa, FL. Seem reasonably priced.
Arnie Baker's "Bike Fit" ebook. If you're a learning-oriented, self-reliant kind of person, this may be for you. A whole lot less expensive than a fitting session, too.
Andy Pruitt's Medical Guide for Cyclists. Ebook. Combines a section on bicycle fitting with a section on injuries / prevention / care.