As promised, the eBook of Flex 4 Fun has been updated to the final version of the text, which was uploaded for printing last week. So if you bought the eBook already, a fresh download will give you the final bits.
If you didn't buy the eBook version already, what are you waiting for? Oh, you want the hardcopy version so that you can enjoy its graphical goodness in the way that Gutenberg intended? Well, you'll still have to wait a bit for that. Even now, armies of typesetters are setting up printing presses to make a run at printing the tome. Look for the book in bookstores and online in mid-September.