This work safe movie (must watch!) demonstrates why men's restrooms are more efficient than the ladies. For the ladies reference, there is a disposable travelaid "TravelMate" that disposes some of the concerns for lack of cleanliness described in Rowan's post by providing the same conveniences that the guys have. Restrooms.org used to have a tutorial on 'How to Pee Standing'.
Ponderings of a Princess have a related discussion on whether or not peeing in the shower is ok right now. Thanks Tim!
