JavaScriptMVC 3.3 will be released in a few weeks and will be using CanJS and the new Steal under the hood. There will be migration documentation to go along with the release, but refactoring should be minimal because we are aliasing can.Control, can.Model, etc to $.Controller, $.Model, etc.
JavaScriptMVC 4.0 will be named DoneJS, but that is at least a few months away from being close to ready.