I'm still playing around with Flex/flash and learning some new tricks.  I decided to try the open source version of Flex/Flash, FlashDevelop.  It basically is just the IDE for the Flex SDK.  I have to say I find it much better, at least for coding.  The intellisense is great.

 Here are some instructions:

http://www.britishideas.com/2008/02/27/first-steps-with-flash-using-the-flex-3-sdk/