C#.net using LINQ

Question

I have a C#.net 2008 web and windows form solution that contains multiple project files. This is an soluttion file that is new to me. All the projects share the dataadapter project. I am told this solution files uses LINQ. However I can not find the LINQ that that must be connected to some data sources.
Thus can you tell me the following:
1. How can I see the LINQ in this application. I must need to select 'view' from the toolbar to have some kind of view Open?
2. Once I can see the LINQ in some data 'connection', what kind of a file do I need to click on to be able to open the LINQ files and work with them?