Now that the PalmOne Treo 650's been officially announced, PalmOne has published a beta version of their PalmOne SDK 4.0, available from their developer program at pluggedin.palmone.com. This SDK adds support for the Treo 650 and the Tungsten T5 devices. This SDK is an add-on to the Palm OS SDK published by PalmSource. You still need our SDK as well as a set of development tools in order to make full use of their SDK. Along with the SDK, they've posted several developer guides, the Tungsten T5 simulator, and the Sprint version of the Treo 650 simulator.
The main developer guide includes information about the new PalmOne Multi-connector used on the new devices. The good news is that serial is still supported. The bad news is that there are no flow-control signals for serial, so you'll have to use software flow control, limiting the speed of serial connections. The guide also talks in detail about the NVFS implementation that's used to support their NAND-Flash based database scheme. One interesting thing I'd not mentioned before: it's now possible for DmCloseDatabase to fail if there's not enough room to write your database changes back out to flash.
In general, the SDK looks like a really nice effort, and there is a lot of information to digest. I'll try to write up some tips on integrating this with both CodeWarrior and PODS in the near future.