At least someone at Apple (AAPL) has a sense of humor.

Less than a week after the iPhone Developer Program rejected as “objectionable” and “defamatory” an application illustrated with caricatures of U.S. Senators and Congressmen, the company has  reversed itself and approved the app.

Bobble Rep for the iPhone and iPod touch was conceived by director Ray (Super Capers) Griggs and illustrated by Mad Magazine caricaturist Tom Richmond. The drawings serve as an entry into a data base of information about the politicians, whose oversized heads bobble when shaken or flicked with a finger. The app is now available for sale here for $0.99.

“I’m glad Apple came to their senses,” says Richmond, “and realized that this app is not only not derogatory or insulting to our congressional representatives and senators, it’s a beneficial program and a little fun as well.”

Richmond spent months drawing the heads of all 540 members of the 111th Congress, including nonvoting members from Puerto Rico and Guam.

Fox News on Saturday was taking credit for Apple’s decision to approve the app, although it was Richmond himself who drew national attention to its rejection earlier this week with a widely read entry in his blog.

See Apple bans Nancy Pelosi bobble head.

[Follow Philip Elmer-DeWitt on Twitter @philiped]