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.
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