If you weren’t already aware I’ve been writing a book on Flex component development which will be published by Addison-Wesley, called Developing Flex Components: Using ActionScript 3.0 & MXML to Extend Flex and AIR Applications. Originally it was targeted at Flex 3; however, as Flex 4 in the soon to be “new kid on the block” I’ve decided to re-write it so it now focuses on the new “Spark” components that are present in the Flex 4 framework as opposed to the “Halo” components that Flex 3 uses.
That said, the original (Flex 3) chapters are now up in the Rough Cuts section on O’Reilly’s Safari digital book service. I’m not sure what will happen to these original Flex 3 chapters once I’ve finished the book – I don’t know whether I’ll be able to release them as PDFs or not – due to contracts and the like, but if I can I’ll add them to the site.
It can now be ordered from Amazon if you want to get in before the rush :p. As I mentioned if you have a Safari account you can buy or access (depending on your account type) the rough cut chapters as they are updated.