Active directory 2003 vs 2008

Hi Brothers/Sisters,
I have been on this site for few months and love this site and the experts who help people here. its really awesome.
I have a questions
Active directory 2003 vs 2008 what are the major differences/Enhancements in Group policy (GPO) in these 2 versions of AD?
Can anyone help me list just the enhancements please.
thank you
