Disclaimer: this is for the brave folks who wish to try things out. So far I've only tested the installer on my own machine and on a clean Windows XP vmware image.
Now for the running bits: here's a first try at getting a workable couchdb installer on Windows.
There were some instructions down at the wiki on how to get all the bits and bobs running together, but parts of it required a C compiler and some rather tedious setup on part of the user. It was also a bit frail, as noted by me trying for a couple of afternoons to get the unit tests to pass.
The biggest problem was that Spidermonkey must be compiled in a specific way (one that wasn't apparent to me at first), which I dismissed at first because the blog containing the steps was down. Also, one must use lowercase paths on the config file, otherwise erlang will choke when trying to open the database files.
The next step would be to create a shortcut on the start menu, get some sensical text on the installer, do some error checking to find out if the prerequisites are installed, and create an uninstaller.
For now, here's the installer for the world to try. Leave a comment if you find a problem or have a suggestion.