New Database, Set Userid And Password

I am creating a new application and just created a new database

Application:  VB.net 2005/ ASP.net

Database:  Sql Server 2005 with four tables

I need to set the userid and password on the database.  How do I do that?

I want to be able to create a SQL connection object in my code and I have something like the following:

<CODE>

Dim objcon As New SqlConnection("server=serverName;uid=;pwd=;database=SomeDatabase")

</CODE>

but the "uid" and the "pwd" are not set on my database. what is an easy way to do this?  thanks