Announcements on Palm OS' death has been done before. Many analysts declared it dead when Microsoft first came out with its WinCE. Yet years after that, Palm OS is still the simplest to use PDA and Palm itself reassured their followers that they're still supporting Palm OS, coming up with the Z22 and the TX. The TX, I can tell you, is an amazing machine and no PPC can hold a candle to it at that price range. The TX is also unbelievably stable so it seems that Palm has learnt its lessons from the LifeDrive. I use Chatter everyday at home to get push email, and it works real great. I can't even find push email softwares for the WM 5.0, and the only thing I hear about is to wait for Microsoft to release their AKU 2, which enables push email with the MS Exchange SP2.
So don't count them out yet.