Oracle Database 11g for Linux is out there now under the OTN Developer License (our motto, with props to Niall Litchfield: "Free to download, free to learn, unlimited
evaluation"). As usual, Windows and other releases are to follow. (Some reporters' fixation with the initial Linux-only release is mysterious, because releasing on Linux first - Oracle itself runs on Linux - is SOP.)
Along with it, you can dive into the first three installments (Database Replay, Partitioning, Schema Management) of Oracle ACE Director Arup Nanda's "Top Features for DBAs and Developers" how-to series, with many more to follow. We intend to complement this content with screencasts as well.
I also had the honor last week of speaking with Dr. DBA himself, Ken Jacobs, about the highlights of this releases and its "place" in the pantheon of Oracle RDBMS. Download the mp3 here.