ISAPI Rewrite 3 Lite Edition has been released on www.iis.net and is available for free.
ISAPI_Rewrite 3 Lite is a Freeware URL rewriter for IIS, compatible with Apache mod_rewrite. It supports nearly all Apache mod_rewrite features. It is used for search engine optimization, to proxy another server’s content, stop hotlinking or strengthen server security.
Features
Offers same syntax and behavior as Apache mod_rewrite, but supports only global httpd.conf configuration
Regular expressions for flexible and powerful configurations
Extremely fast and highly scalable pure C++ code
Benefits
Search engine optimization
Prevent content leeching (direct linking)
Hide file extensions
Block specific hosts, referrers or annoying robots
Content negotiation – serving different files for different language or different browsers
Download it here.