How to do System.Net.NetworkCredential for ASPX Pages

[DS]

Hi,

I have two created Websites:

WSA – With only Integrated Authentication turn on
WSB – With Anonymous Access and Integrated Authentication turn on

For user that comes to WSA, if they have a NT Credential I redirect
them to WSA. For user that comes to WSB without NT Credential I want
to push them to a login page and validate their input against a DB and
then retrieve their mapped NT Account and log them into WSB.

Couple Caveats:
WSA and WSB are in different domains
WSB is a WSS site (Windows Sharepoint Service)

I have done this with web services but never done this via Asp.net.
NetworkCredential oNC = new NetworkCredential(@"DN\UN", "PW");

Any suggestions are welcome.

DS