How do I add a HTTP module in ASP.NET?

<?xml version="1.0"?>
<configuration>
    <system.web>
        <httpModules>
            <add name="ModuleName" type="ClassName, AssembleyName" />
        </httpModules>
    </system.web>
</configuration>

Example:

<add name="URLRewriter" type="HTTPModules.URLRewriter, HTTPModules" />