ive noticed alot of sites use rewrite rules in apache for seo purposes. for example, in vbulletin there is a mod that rewrites all requests to a url like blah.com/forum/post.php?id=2394234 TO blah.com/bicycle-shopping-etc.php
therefore, you have all the seo benefits of a good address, without 1000's of files. how can you do something like this in iis?