Pictures of Halle Berry's character in a bikini have surfaced on Wireimage. And yes, before you ask, Jinx's bikini is a homage to the bikini worn by Honey Ryder in the first Bond adventure, Dr No.
The Mirror has published a report about the scene saying Jinx "even copies the moment where Andress seductively swept her wet hair back into a ponytail".
Thanks to 'Jaime Bond', Rob and 'John007' for the information! You can discuss the bikini in this thread of the Die Another Day Forums.