Hi...
To do this on IIS you should read the IIS manual on Technet... half way down the page you'll read.
Redirect Wildcards
You can use redirect wildcards to match any number of characters in the original URL. Open a directory's property sheet in IIS Manager, select the Home Directory, Virtual Directory, or Directory tab, click the A redirection to a URL option, and insert the wildcard character (*) in the Redirect to text box. Begin the destination URL with an asterisk (*) and a semicolon (;), and separate pairs of wildcard characters and destination URLs with a semicolon.
For example, to redirect all requests for /Scripts/Filename.stm to a single file called Default.stm, and to redirect all requests for /Scripts/Filename.asp to a single file called Default.asp, type the following in the Redirect To text box for the /scripts virtual directory:
*;Filename.stm;/Default.stm;Filename.asp;/Default.asp,
HTH - Mark