via the Google Maps API Google Group:

I'm the developer of the US Voter Info mapplet and gadget (the front end,

not the API). I'd be happy to answer any questions about it.

I don't know of any public documentation on the polling place API either.

There is an internal document - I'll find out if it can be released. As

Barry mentioned, you can use Firebug or (my favorite) the Fiddler debugging

proxy server to scope out how the mapplet and gadget call the polling place

API.

You can also get the source code for the mapplet and gadget and see how it

works. The code is here:

http://code.google.com/p/election-maps-2008/source/browse/

Or:

http://code.google.com/p/election-maps-2008/source/checkout

The main source code is in poll411-map.js. The mapplet is

poll411-mapplet-gc.xml and the gadget is poll411-gadget.xml.

The code goes through several steps to get the polling place info. The

polling place API is fairly strict about the address formats it will accept,

and the addresses it gives back come in several different formats. Some have

a complete address, others have only the street address and maybe the city

or maybe not. (This isn't the fault of the API; different states provided

data in different formats and various degrees of completeness.) So the

mapplet code does this:

1) It geocodes the address you enter, both to get the lat/long and more

importantly to get a more complete, cleaned up version of your address.

2) It passes the cleaned-up address to the polling place API.

3) If it gets back a single valid result, it inspects the returned address

to see if it has anything that looks like either a zip code or a valid state

abbreviation. If those are missing, then the code appends the city and state

that it got from step 2 (the assumption being that the polling place is in

the same city as your home).

4) Finally, it runs the resulting address through the geocoder again, to get

a cleaned-up version of that address along with its lat/long.

To find the relevant code in the mapplet, look for the geocode() and

lookup() functions that do the basic geocoding and polling place lookup, and

the findPrecinct() function that puts it all together.

Hope that helps, give me a shout with any questions...

-Mike