I've just gotten my hands on the TotalTraining DVD "Flex 2 Rich Internet Applications" presented by James Talbot and its an absolutely wonderful training resource. First heard about this title during the Adobe Community Summit this summer at the Adobe HQ in San Jose when we had a two-day crash course on Flex 2 by the man himself.
Tend to be a bit biased against video training as opposed to the real thing in a classroom setting but must say I didn't have this feeling after watching this training.
If you're a somewhat experienced Flex 2 developer as I'd consider myself the first two lessons and the "Flex fundamentals" section probably won't be too interesting. From there the course moves swiftly on to some more indepth topics giving you a solid basis to start developing with Flex Builder 2.
From lesson 10 onwards I feel this title gets really interesting talking about application architecture, data handling, custom formatters etc.
Would highly recommend getting this training DVD if you're interested to get into Flex 2 development or want some best practices on how to improve your current work. Hope they've got a similar title in the works specifically for ActionScript 3.