Because SO does not let me to post many links I have posted it to Axaptapedia
Download the "Inside Dynamics Ax 4" free ebook from microsoft and read then read What's new about changes in Ax2009 (X++ is pretty the same)
Some other cool resources:
axaptapedia
code.msdn.microsoft.com/axcodesamples
Paper Books :
Inside Dynamics Ax 2009
Managing supply chain using Dynamics Ax 2009
Is you have access to partnersource or customer source, go there and read development and financial trainings
