Q:

Global Class to access Variables

We like to have a global instance of a class and would like to access across the application (in different forms etc)
What are the different possiblities? (other than static class).

A:

It sounds like you want the Singleton pattern.  Depending on your application you want to be careful though.  You only get one instance of it, and this can cause unexpected behaviors with multiple threads etc. (there are other drawbacks too, my main point is that you have to look at the downsides of the pattern also).
C# patterns: http://www.dofactory.com/Patterns/Patterns.aspx 

