The jQuery Mobile team just announced the availability of Beta 1. You can read about all the changes on their blog. Note that jQuery Mobile 1.0 will require jQuery core 1.6 as a baseline, so you might need to also update your copy of jQuery as well.
So, that means I need to go and manually update my copy of Dreamweaver to support the latest version. Greg Rewis has an excellent post on how to update Dreamweaver. The post refers to JQM 1.0a3, so just insert JQM 1.0B1, and you should be good to go.