This is a great new feature of ASP.NET 2.0. How many times have you needed to redirect one URL to another? Maybe redirect a static url to another url to another page with an ID? The new urlMappings element in the web.config allows you to do just this. Take a look at this example below.
<add url=“~/LAX.aspx” mappedUrl=“~/local/index.aspx?LocationCode=LAX” />
<add url=“~/specials/walmart.aspx” mappedUrl=“~/specials/9994.aspx” />
The first entry maps LAX.aspx to the local site page with a LocationCode query string parameter of LAX. The second maps the page walmart.aspx to 9994.aspx (Remember the ~ operator maps to the root of the web application). This will be extremely useful in search engine placement in the future. It will also allow us to make custom urls for customers without having to do special Rhythmyx publishing configurations.
Read the complete post at http://www.dotnettipoftheday.com/blog.aspx?id=116