This question came in to me via Stefan Richter yesterday on Twitter and I thought I'd use the blog to answer in a bit more detail. He asked:
liking jqm so far but have yet to figure out how to keep my business logic separate from markup using cf for backend)
PhoneGap allows you to take simple HTML and create a mobile application. While we may be used to the idea of having HTML to build out our sites, you have to change your thinking a bit when it comes to a PhoneGap application. Your HTML is running within a wrapper on the device itself. That means any logic built in ColdFusion (or any server side language) is not going to be available to you... directly.
Whereas in the past you could have a simple detail page that queried the database based on a URL parameter, your PhoneGap app is - in ways - like running a HTML file downloaded from the Internet.
If this does not make sense, please post a comment!