In favor of keeping the penny:

Americans for Common Cents (supported by the zinc industry)

Some opinion pieces available on the web:

Penny Dreadful, by David Owen in the New Yorker (March 31, 2008)

Common Cents, by Joel Stein in TIME magazine (July 17, 2006)

Abolish the penny, LA Times op-ed (June 17, 2006)

Should the Penny Go?, by Annelena Cobb, CNN/Money Staff Writer (April, 2002)

Cents Sensibility, by Mark Lewis, ABC News/Forbes (July, 2002)

Ban the Penny, by Mark Lewis, Forbes (July, 2002)

Americans Still Flip Over Penny, by Roy Wood, Cincinatti Post (July 2001)

Are you a penny picker-upper? , by Dayana Yochim, The Motley Fool (Februay 2006)