You'll find that the sites listed here are great places to expand your knowledge. In addition, most have links to other similar sites.
Although this is targeted to the Director user, you'll find high-quality articles on many subjects, including many on Flash.
You can't beat going straight to the source. Also, be sure to check out the Macromedia Exchange, where you can find more components (www.macromedia.com/exchange/flash) as well as the DevNet resource center (www.macromedia.com/devnet).