The only thing that I haven't seen mentioned yet to help with the mashing uphills is to really focus on the LIFTING of your pedals (for those with the clipless pedals). Which reminds me of another question I have myself... Why is it we call the pedals that actually CLIP to our shoes "clipLESS".
Anyway, I've found that those big Hammy muscles can really propel you up the hill by focusing on the lift verses the "mash" although you lose all the benefits of our considerable girth. I think that alone has made me much better at getting uphill for the more enjoyable ride down the other side.
my two cents...