Ditto on spin class really helping you with this. Lots and lots of "climbing" both in and out of the saddle. Lights, music, friendly female voice telling you to hang in there. Good times.
IMO, hill training in spin class somehow manages to be harder than actually riding a hill. Must be something about the flywheel or being out of the saddle for 15 minutes straight. After a few spin classes, most hills I encounter around here are a breeze.