Help with XP/IIS/ASP.NET configuration

I have setup an XP box to run my ASP.NET application.  My objective is to
run the application on the XP box and have it accessible to the local
network for internal use.  I've setup the Virtual Directory and added the
following users and enabled 'Anonymous Login' and 'Integrate Windows
Authentication'.
- NETWORK
- ASP.NET
- NETWORK SERVICE
- IUSR_MACHINENAME
- IWAM_MACHINENAME

I've also added the following statements into my WEB.CONFIG file.

<identity impersonate="true" userName="DOMAIN\TESTUSERACCOUNT"
password="TEST"/>

<authentication mode="Windows" />

<authorization>
<allow roles="Everyone" />

The IDENTITY IMPERSONATE exists exclusively to help get past the SQL Server
not accepting NULL user login.  I'm able to call up the application using
HTTP://LOCALHOST/TESTAPP, and I'm able to run it using
HTTP://MACHINENAME/TESTAPP.  However, it keeps prompting me for a
Windows/Domain level login/prompt everytime I use the
HTTP://MACHINENAME/TESTAPP from the network.  Is there something I'm
missing?  Please help.

TIA
John