<p>Are there any favorite online references or good introductory and intermediate/advanced books on this topic that you could recommend to me?
I'm a java developer, so I'm looking for something which would be familiar as possible as to me.</p>

Essential ActionScript 3.0
, by Colin Moock
Programming Flex 3: The Comprehensive Guide to Creating Rich Internet Applications with Adobe Flex
, by Chafic Kazoun, Joey Lott
Also check the books section on Flex.org
There are some good video tutorials on lynda.com
http://www.flex.org
http://www.adobe.com/devnet/flex