Simplest way of doing it? igLoader from IndiePath. You pretty much don't have to do ANYTHING to the code. Just make sure it runs in a window and that the window is not resizeable. Just set up a few bits and pieces with the site and the igLoader files, but it's about an hour from a BlitzMax game to a webgame.
http://www.igloader.com/
http://www.igloader.com/