I got the news from oracle newsletter. However, it's still in beta version for now and the previous stable 10g version still available (link below). I haven't tested it yet but will try to find the time to test it out (or perhaps wait for the stable release) and see what are the new features available.
Oracle XE 11g : http://www.oracle.com/technetwork/database/express-edition/11gxe-beta-download-302519.html
Documentation for 11g : http://download.oracle.com/docs/cd/E17781_01/index.htm