NBC TV reporter (and former Wash Post writer iirc) Tom Sherwood also beat me to covering the Herblock exhibit -
He interviews my friends Martha Kennedy and Sara Duke, and you get a good sense of what the exhibit looks like.
ABC has a text story on the exhibit - "Herblock: Cartoonist Who Coined 'McCarthyism' Honored at Library of Congress; Master of Editorial Cartooning: Herbert Block Cartoons on Display," By LINDSEY ELLERSON, Oct. 13, 2009.
As does the sadly-diminished Syndicate World section of Editor and Publisher - "Library of Congress Opens 'Herblock!' Exhibit," By Elaine Williams, E& P Online October 13, 2009.