If you're an ISV or Developer looking at Dynamics AX 4.0 customisation and development then please check out these recent Channel9 videos by Michael Fruergaard Pontoppidan, one of the authors of "Inside Microsoft Dynamics AX 4.0".

Model Driven Development in Dynamics AX 4.0

Dynamics AX 4.0 - Unit testing

Dynamics AX 4.0 - 3-tier Development

Dynamics AX 4.0 - Smart customizations