Getting Sitellite to run on Microsoft IIS is likely possible, but almost certainly not simple. A recommended prerequisite to making an attempt is a strong familiarity with both PHP and IIS. After all, you'll be required to maintain and support the installation afterwards.

The issue is specifically with two of Sitellite's features:

1) The ability to have a URL like /index/pagename resolve to the file /index instead of coming up with a 404 error. You'll need an IIS equivalent to Apache's AcceptPathInfo directive. A quick Google search turned up the following for:

http://groups-beta.google.com/group/microsoft.public.inetserver.iis...

2) A way of telling IIS to treat the 'index' file as a PHP file. This may be possible by setting the default file type to PHP instead of text/plain, but this technique does have the drawback of requiring file extensions for all non-PHP files. I've also seen people use a PHP 404 handler to get this to work, but I'd recommend the default type solution before this one. Some other folks suggest you'll need to find or write a custom ISAPI filter to do this, such as the one found here:

http://www.isapirewrite.com/

Beyond these two issues, there may be some differences in PHP's $_SERVER array between Apache and IIS, but these should mostly work the same.