From what I have read it seems that FPAA could provide a way to design a "programmable" analog computer, but are there any online resources on how to implement such a system?
Don't expect to build analog computers.
They are mainly useful for custom reconfigurable analog filters & some schemes with opamps, that's it.
Can't suggest any resources except datasheeds on your chips :-)
As someone who actually worked on designing a programmable analogue computer in the first year of my PhD, I'd say that there are interesting applications for such machines. However, like what some of the others have said, it's rather niche.
You need to start to think of analogue as analogous instead of continuous. Once you do that, you should be able to design analogue computation circuits with FPAA. However, there is limited modern literature on this matter. You would need to go further back to the 1950s or so to find books on the fundamentals of designing analogue computers.
You can find some newer papers from this academic.
I have a Cypress PSoC series 1 programmer w/ 2 chips that I bought for around $50. I haven't gotten around to using them myself, but I know somebody who his using them on the data acquisition side of a prototype digital musical instrument. He uses it to amplify and digitize signals from fiber-optic sensors.
There's also a project in the book iPhone Hacks that uses a series 1 PSoC to make a sensor input to the iPhone using the microphone jack.
Last I checked, the companies that used to make pure PGA's went out of business.
EDIT: This post at SparkFun has some information: http://forum.sparkfun.com/viewtopic.php?f=5&t=577
FPAA's are a rare breed. Ther have been three other companies that tried to create these. One went under (they also wanted $20 a chip!), one was reorganized and the FPAA "disappeared" from their product lineup, and the last one, Zetex, still exists, but have one product and it doesn't appear to be all that well supported.
EDIT: Oh, I forgot about this guy: http://servenger.com/products/index.htm – programmable analog signal processing board.