You can download the 30 day fully functioning trial now and the products will be shipping to all as of March 25th 2008. Give the products a trial and see what has changed and what is new. You can use the new ribbon and task based user interface and even customize it or turn it off and use AutoCAD the way you have always done, your choice.
AutoCAD Home Page www.autodesk.com/autocad
AutoCAD 2009 New Features Workshop
AutoCAD 2009 30 Day Trial
System Requirements. You can download the 64-bit version or order the trial on CD or DVD.
AutoCAD 2009 Trial Download FAQ (pdf - 41Kb)
AutoCAD LT 2009 New Features Workshop
30 day trial download coming soon check the AutoCAD LT Home page www.autodesk.com/autocadlt