Alternatives to the fancy pants Hydropel and Bodyglide sticks:
Vaseline....like Craig mentioned, proven, hydrophobic, inexpensive, and readily available....like currently in your medicine cabinet.
Desitin or Boudreaux's Butt Paste.... yep, baby diaper butt cream, gentle enough for a baby, strong enough for a hiker.
Udderly Smooth Original or Chamois Creme.... used on cows udders and other milkable creatures, keeps them moo tatas happy, should keep hiker butts happy.
Bag Balm.... cheap, proven, works for livestock, readily available. Used by runners and cyclists forever, should work for walking.
Desenex CREAM.... yes, the anti-fungal cream, works magic on baby diaper rash....not sure why, also works for preventing chafe.
Chamois lined compression shorts.... if it's really that bad then get something to prevent it.
*Just realized people were looking for solutions on their feet....oops. I have no idea if the above items work on feet... probably do, someone test them.