Research in Motion (RIM) has announced the RIM 957 Wireless Handheld, a device that is wireless and has PDA functions. Its price ranges from $349-$499 and will have always-on capability and instant notification of new mail. Here's the press release about the RIM957.
I don't believe the Proton will be a Palm killer (why does every analyst use that phrase?) as the Blackberry as of yet has been more of a niche device, selling in the low 100,000's. It would make a cool Springboard module though. This C|Net article also mentions that a wireless Springboard module is expected from Handspring at some point.