Channel 9 Videos on AX

Model driven development in Dynamics Ax
http://channel9.msdn.com/ShowPost.aspx?PostID=235518#235518
Exception handling in X++
http://channel9.msdn.com/Showpost.aspx?postid=273765
Application fundamentals in Dynamics Ax
http://channel9.msdn.com/Showpost.aspx?postid=284365
Dynamics Ax 4.0 – Unit testing
http://channel9.msdn.com/Showpost.aspx?postid=247301
Dynamics Ax 4.0 – 3-tier development
http://channel9.msdn.com/Showpost.aspx?postid=259048
MorphX best practices in Dynamics Ax
http://channel9.msdn.com/Showpost.aspx?postid=292988
Smart customizations in Microsoft Dynamics Ax 4.0
http://channel9.msdn.com/Showpost.aspx?postid=267428

Other Dynamics videos -
Video from Jakob Nielsen, director of UX (User experience) on Dynamics team –http://channel9.msdn.com/Showpost.aspx?postid=175501
Video from Mike Ehrenberg, Architect of Dynamics Team titled 'Architecting next generation of Dynamics' -
http://channel9.msdn.com/Showpost.aspx?postid=175509
Video from Ulrik Molgaard Honore, Program Manager for the Production Planning team in Dynamics Ax
http://channel9.msdn.com/Showpost.aspx?postid=272229