I've got a great question related to a previous post:

Is there anyway to send the username and password with the URL request to the router so the user is not prompted for the login?

You can specify username and password as part of standard URL syntax http://username:password@host/rest-of-url, so to execute a show ip interface brief command you could use this URL (after configuring multilevel web access on the router):

http://guest:guest@router/level/1/exec/show/ip/interface/brief

Note: this syntax no longer works in Internet Explorer with latest security patches, please read http://support.microsoft.com/kb/834489 for more information on how to re-enable this behavior.