Okay ... this one seems to be making the rounds of various lists and blogs and a slow news day allows me to track it down. The source appears to be a passing remark in a Washington Post article:

Reporters traveling with Secretary of State Condoleezza Rice on her recent trip to visit our new close friend in North Africa, the colorful and wacky Libyan dictator, Moammar Gaddafi, were handed lovely paper cocktail napkins with their in-flight libations. The napkins on the plane, also called Air Force Two when Vice President Cheney uses it, have a lovely rendition of the Great Seal of the United States -- one of Rice's duties, after all, is "keeper of the Great Seal."

But "e pluribus unam?" Out of many . . . unaminous? Or maybe it should be "unum" -- as in "Out of many, one."

... a political column in the Guardian adds a bit of detail:

Is Condoleezza Rice, who was often spoken of as a potential Republican presidential candidate, fully on board with the Sarah Palin phenomenon? She seems to be dropping hints that she might be still available, for now, or perhaps when the cavalcade rolls again in four years? On her recent trip to Libya on Air Force Two, the napkins that came with the drinks bore the great seal of the US; except that instead of E pluribus unum "From many, one", the legend read E pluribus unam. Most took this to be a misprint, but Latin scholars noted that unam is a feminine form. From many, one woman, is it? Which one?

The only genuine Latin scholar I can find online who has commented on it is Dennis over at Classical Values, who notes (correctly) the 'unam' is essentially meaningless when lacking a transitive verb (unum, in the Great Seal makes more sense when taken as nominative).