There are series of videos on MSDN called How do I? to provide online help to developers.
The good news are that they expanded the area of coverage of those videos and VSX is now covered.
So if you want to learn VSX you can download the series and start watching them in your ipod, zune, xbox 360, etc.
Right now you can only download 3 of them, but for sure there are more to come.
Pablo
