Progressivism: A Working Definition

There is much confusion in political discussion today about who or what can be classified as a "progressive". Glenn Beck daily demonizes progressives as anti-American, seeking to destroy the very foundations of our country, comparing them to Nazis, Communists, and Stalinists. How could someone think there's any good reason to make such comparisons? And what is the relationship between liberals (last decade's scourge of the right-wing) and progressives? Is there a difference? Or are progressives simply liberals with a shiny new name?