How do I set the default page of my application in IIS7?

Just go to web.config file and add following

<system.webServer>
    <defaultDocument>
      <files>
        <clear />
        <add value="Path of your Page" />
      </files>
    </defaultDocument>
</system.webServer>

1. On IIS Manager select your page in the Sites tree.
2. Double click on configuration editor.
3. Select system.webServer/defaultDocument in the drop-down.
4. Change the "default.aspx" to the name of your document.

Karan has posted the answer but that didn't work for me. So, I am posting what worked for me. If that didn't work then user can try this

<configuration> 
    <system.webServer> 
        <defaultDocument enabled="true"> 
            <files> 
                <add value="myFile.aspx" /> 
            </files> 
        </defaultDocument> 
    </system.webServer>
</configuration>