Download it from

http://code.google.com/p/mongoose/

The default behavior of mongoose after you execute it is that it will serve the files in the same directory as the exe on port 8080.

When mongoose starts, it adds an icon on a systray. Right click on it, choose install. That would install the service.

From the systray icon, you can also make Mongoose save its current .conf file for editing.

Note that Mongoose supports both non-secure and secure web connections (https).