newbie question for C#.net

Question

Since I am new to c#.net 2008 but I have worked a little with visual basic.net 2005, I have the following questions I would like to ask:
1. When I am looking at a .sln file that I will be maintaining a work, I can see there are lots of static void Main() methods in a file called program.cs throughout the solution in separate folderts. Can you tell me the purpose of this kind of code? Does this instantiate an object, is this a class libary member?
2. When running the C#.net 2008 professional version windows application, how do I know which 'main' method is being called?
3. When looking at this sln, I would like to determine all the different ways to run this .sln application there are. To do this would I look at the different ways there are to run the application (release, debug, configuation mange), would I use the object explorer? How would you recommend I learn how this .sln is executed