C# Web Service Session

Question

Hi Forum,

I've just created a windows form application in C# and a web service project (Both in one solution) in VS 2008. Everything is working fine at the moment and I am able to call the web methods in my web service class from the forms.

I'm trying to find a way to create a session id during the login process. For example a user login, and a session ID is generated and is used to communicate between the application and the service. Is there a straight forward way to do this? Or can someone point me to a right direction?

Thanks in advance
Vish