AxErd - New site with AX2012 R2 entity relationship diagrams
A small commercial for those who missed the new site that provides database entity relationship diagrams for tables of Microsoft Dynamics AX 2012 R2.
Now you can get diagrams like this - prebuilt for key areas:
This is where you find it: http://www.microsoft.com/dynamics/ax/erd/ax2012r2/
Also check out this blog post: http://blogs.msdn.com/b/x/archive/2013/05/23/announcing-the-axerd-website-for-dynamics-ax-2012.aspx