What is in Unity 3 besides the licensed technology?
various things talked about on the blog and the various threads. as deferred rendering, the new surface shader system etc etc.
not all of that is available in the free unity though (like deferred thats pro only)
if you are interested in the feature delta, you will have to wait till release when the page will focus on unity 3 on that information. (at that point you can also read more about the available stuff)
Will there be new tutorials for version 3? I noticed that the older tutorials on the site do not work for version 2.6
Where are the developer blogs?
The blogs are available here. It is likely that the old tutorials will be updated or replaced soon.