I've been to Antarctica twice. My trips were aboard a ship, and we would make shore landings 2 or 3 times a day, for 2-4 hours at a time. The trips were run during the 'summer' months (in Antarctica) of November to March. It was often sunny, and the temperatures ranged from about +4 to -15 degrees Celsius the times I was there. (To a Torontonian, those are not terribly cold temperatures).
As we were really only 'outside' for those 4 or so hours at a time, I never had a problem with my (film) camera or batteries. I would carry spare batteries (I was using CR2's) with me, but it was rare they would need replacing. As other posters have mentioned, you keep them in a pocket close to your body, so they stay warm. I kept my 28-300 lens on at all times, as I liked the range it provided and I didn't have to keep changing lenses. I know that some people who were changing lenses sometimes had their cameras freeze up on them (perhaps from cold air getting inside.)
If you're on a ship, most have a computer on board, with 'universal' cardreaders, where you can download your pics to a disk or jumpdrive. So you might want to take disks or jumpdrives with you, and a cardreader or your cable, if you won't be taking your own laptop. And don't forget your recharger for your batteries (you'd be surprised at what people would forget!)
The ships I was on also had lecturers/expedition leaders who were quite good at photography, and they were always pleased to help you with any questions. As the snow can be quite bright, you have to compensate for that. I just kept my camera in its case, in a plastic bag, in my knapsack when in the zodiac ferrying us from ship to shore. You might also want to invest in a drybag for added protection if you're going to be near water: they're light and inexpensive. I found no real need (on the type of trip I was on) to take a hard Pelican case, as it would just be unwieldy when ashore. Once I was on shore, the camera was around my neck the whole time. (Actually, I'd often have it around my neck, tucked into my jacket and lifevest, while in the zodiac so I could take pictures then too).
Hope this helps! I'm sure you'll have an awesome time. And shoot me an email if you have any other questions I might be able to answer.
