One can only guess as to the level of support the next version of Dreamweaver will have for PhoneGap… But if you are already doing mobile development in Dreamweaver CS5.5 and Phonegap, Adobe has released a new extension that leverages the PhoneGap Build service. For those unfamiliar with the build process with PhoneGap, there are two versions: build locally (aka install and manage the native SDKs) or the build on the server (aka PhoneGap Build). This extension is for the later development model.
Here is the full announcement from Adobe.
I have not tried this extension out yet, but hope to shortly.