<p>How can I get data from a database that I can only access through an ODBC Data Source (DSN) in T-SQL MS SQL Server, any version?</p>

The selecting is the easy part, but the real question is how do you connect to the datasource.
First, where are you selecting data from?  Are you writing code, or just using the Query analyzer tool (2000) or Management Studio (2005)?
You'll need to setup your connection to the database regardless.  If you need help with the connectionstrings to a DSN, the site www.connectionstrings.com is very helpful.  Otherwise, from a query tool there will be dialog boxes or wizards to help you.