My at-work dictionary has a use note: "Traditionally few and fewer are used only before a plural noun few books; fewer people and less is used before a mass noun (less sugar)."
This is best exemplified in the story about the minister of this small church in rural Florida who discovered that an addition to his family had strapped beyond repair the ability of his flock to keep him and his family in food. So he looked around for a job, and ended up at the local orange grove. The owner of the orange grove was impressed with his common sense and his ability to follow instructions, and hired him to sort through the oranges to find only the very very best, which would be sent to the White House for use in making orange juice for the President and his family. His job was to take only the top one percent of all the oranges.
A couple of weeks after he started work one of his flock came to the orange grove and was a bit perplexed. "Reverend," said the churchgoer, "I thought you were out doing the Lord's work."
"And I am," responded the preacher, "For did we not learn that truly, many are culled but few are squozen?"
Of course this doesn't at all exemplify the difference between few and less, but it did give me a chance to tell one of my favorite stories.
