There are a couple of other ways to move actions from one project to another.
In context mode, with the Project column visible, you can just enter the new project by tabbing to the right field. With an action selected in planning mode, Cmd-Opt-R will take you to that action in context mode. (So far there's no Project column in planning mode, so you have to change modes for a keyboard-only solution.)
You can use the inspector to set the project of the action in either mode. This involve clicking on the inspector to give it focus, but it does eliminate the long drag, which can be. (a drag, that is)