Lord knows I'm awful at climbing, but one of the most effective workouts I had was to do hill repeats/intervals in this pattern -- 3 x 3 minutes, with three minutes in between, 3 x 2 minutes, recover for 5, then 3 x 1 minute. By doing the long one three times, you get to see what type of gearing works best for you -- I would do one in a big gear/low cadence, the next one spinning, and the last one a combination. It helped to see which way i could maintain for the whole 3 minutes.

Hmmm. I haven't done these in a while. It might be time to start up again.