2002 was my first convention, and the best advice I got beforehand was "Do not wear white pants!"
There were many white skirt and blouse/sweater combinations. I found it really challenging to locate a white dress or suit. Ann Taylor had a great white pique dress, which unfortunately wasn't available in petite sizes -- I counted at least ten of them at Convention. I found a cute, plain sheath dress on Talbots.com, but definitely needed a sweater in the air conditioning.
Just be careful about lingerie, and pack a slip! There was one attendee who must have overslept or gotten dressed in a hurry, and was wearing animal print undies under her unlined white linen dress.
See you in Kansas City!