I'm Andy Warren, currently a SQL Server trainer with End to End Training. Over the past few years I've been a developer, DBA, and IT Director. I was one of the original founders of SQLServerCentral.com and helped grow that community from zero to about 300k members before deciding to move on to other ventures.
This article by Andy Warren is an introduction to DSN's; what they do, how they work, and where they are stored. Also pick up some ideas about how using a File DSN might save you a lot of administration!