Ironically the most exposed is Doug Holland's at Intel's blog site :) - nice and very brief overview.
More info at Channel9 video provided by C# GoF :). The most striking facts are:
- dynamic typing is for better Office interaction,
- optional parameters and named arguments are evil, provided for VB developers to ease Office development in C#,
- covariance and contravariance are only interesting (good) changes in language, but it should have appeared in previous versions of C#.