ODBC Data Source SQL Server Connection - Login Failed For User
My answer... From my comments:

The issue was that the server was set to "Windows Authentication Mode" only. To fix this I 


Right click the server - > Properties 
Click "Security" in the left side of the "Server Properties" dialog 
Changed server Authentication to "SQL Server and Windows Authentication mode" 
Clicked "OK" 
Restarted Associated services. At first I forgot to restart the services, so I was still getting the error, but now I am able to connect without an issue. This was very helpful: http://support.microsoft.com/kb/555332