I know I'm not Ed or Chris, but migration to JSF2 really depends on what has been done in the view layer. Were you using
JSP or facelets before? If it's facelets the move is really pretty easy. If it was JSP then the move will be harder, especially if there were scriptlets involved. Taglibs will also need to be converted.
The rest, backend logic, custom JSF components, phase listeners, managed beans, valudators, converters, etc should migrate over pretty easily (in many cases without any work).