You don't need to use apache's rewrite module. All you need is the ability to force an application to be used when a directory is accessed. I've done this in Apache using this line:
AliasMatch /article/(.*) "/web/liquidcode.net/public-html/main.html/$1"
This says that when /article/ is in the URL that the user sends then the file main.html should be run and the values /article/* are sent to it. Now in my main.html I just do this:
$url_array = explode("/", $REQUEST_URI);
$section = $url_array[1];
And get the pieces of the URL that I use to display the proper page. I don't know how to do this with IIS or PWS. You should also check the articles section of this board for the articles (I belive there are 2) on building dynamic pages with search engines in mind they are very helpful.