Accessing IIS's MIME type list?

How can I access IIS's MIME type list?

I want to serve a file from my ASP.net application, which I can do by using
TransmitFile.  However, the content-type will always be set to text/html.  I
want to autodetect the MIME type for the file the same way it would be if the
file were being served statically.

At the moment, I can do this by writing a zero-length file of the same name to
my website, then making a WebRequest to it and reading the WebResponse's
Content-type header, then using that as my Response content-type header. 
Obviously, this is a horrible hack and there is surely a better way to detect a
file's MIME type as according to IIS?  Could anyone tell me how to do it? 
Thanks!

Try www.iis.net.

Jeff