>What is one required to do as a beta tester?

Speaking as a past beta tester, and not as an MS employee, you have to test the product. If you can use it as your everyday development environment, and then rebuild your projects in the currently released version, that should work. When you have a problem, you can't just say "this doesn't work" (well, ok, you can, but it won't get filed as a bug): you have to be able to say "if you do these 10 steps, it will behave this way, and I think it should behave that way". If you don't post results of your testing, you probably won't get later beta releases.

Someone mentioned that MCSPs (and MCSDs) get betas: they don't get all of them. I've worked with betas long before they were on MSDN or TechNet...