Useful sites I've come across in the past

http://www.javaspecialists.co.za Dr Heinz Kibbutz

http://leyton.org/ Richard Leyton ( I think he's a Doctor too)

http://www.javapassion.com/j2ee/ Sang Shin has interesting on-line tutorials which I've been meaning to take. He works closely with Sun in as much he gets to use their classroom/ lab facilities.