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>

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