I wanna take part in open source project. I have 3+ years expirience in .NET programming (developed frameworks for automation test). Also I have 1+ year expirience in Java and Pyton programming (developed automation test). Who can recommend such projects?
Have a look at CodePlex and Sourceforge. Take a look at the projects on there and find one that interests you. Normally getting involved with a project means just submitting bug fixes initially which get merged into the gold copy. Once the project team gets to know and trust you, they might accept an approach from you to join the team.
Alternatively, you could always start a project of your own off in an area that interests you.
Depends on how much experience you carry and what have you worked and learn't previously.
Basics: Knowledge of GAC and assemblies, plus http-handlers on IIS side
C#: Concept of Delegates and Generics should always be clear and try using as-many demo examples of same.
ASP.Net: General 2.0 features like Master-Pages, Themes and Site-Navigation
There is much to learn depending on what you are going to end-up working on.
They will be used by more and more developers and will become the standard for the next thousand years; or not! I don't think there are many people who can tell the future. However, if you want to know about the present, then look at some of the products that are on the market that make use of these technologies, and the books written about them.