Authenticate against Active Directory

We are writing an enterprise application in which the user logs in by entering their username and password in a form. The user will enter their actual Active Directory credentials. I want to pass the username and password to a stored procedure that will check for a valid user account in an Active Directory. In Sql Server 2005 I know I could write a small .NET library that uses System.DirectoryServices , register it in SQL and access it from an stored procedure.

Can it be done in Sql server 2000?

The reason we are not just autheticating in the .NET code of the application is that we found that it does not work on Windows 98 cleints, hence the need to go through sql server.

Thanks

In SQL Server 2000, you can write an extended procedure. See http://msdn.microsoft.com/library/default.asp?url=/library/en-us/createdb/cm_8_des_07_9rxv.asp for additional information on extended stored procedures.

Thanks
Laurentiu