Last month I posted “What’s New in” series on http://tahiti.oracle.com But for some of us reading is not the best way for learning, and we have another excellent resource with Oracle; http://www.oracle.com/technology/obe/demos/admin/demos.html
You can use this page to play mini lessons to learn how to use various new features of the Oracle database, and they keep adding demos to this site on a regular basis and it was Last updated at 01-Feb-2007.
Extract(Read) > Transform(Test&Apply) > Load(Learn) Blog 
The brains behind these very nice demos is Jean-Francois Verrier who is the courseware developer fro Oracle Eduaction for teh New Features, RAC & Performance Tuning classes’ coursware.
Here is a list of demos available there:
http://sysdba.wordpress.com/2007/01/15/new-demos-on-10gr2-rac-available-on-otn/