The first thing I do is hit the "Trac Control Off" button. I HATE that goddamned system. If it's so slick that the car's gonna come all the way around instantly, it won't catch it in time anyway. And if not, and I'm trying to get across and intersection quickly, I DON'T want it cutting all the power on me. I can manage the rear end slide no problem. But, leaving it on doesn't hurt the engine any - as someone alluded to above, it just cuts back your timing and/or gas to limit the engine output - sometimes severely.
I grew up practicing 2 and 4 wheel drifts on deserted side streets any time we got a decent snow. Seriously...from about 15 or 16 years old on, a good friend of mine or I would show up at the other's house, and we'd spend the whole evening sliding around town. Good practice for when you need it. I still do it from time to time. If you're comfortable with this approach, and with the car sliding around, just switch the damn thing off. If not (and I don't want to be responsible for getting you killed, so be conservative) follow the above advice and add some weight to the trunk, and make sure you've got good tires. Good tires are good advice whether you're gonna take it easy, and safely, or plan on slippin' and slidin'. A tire that's down to half it's effective tread life (i.e., still 3/16 to 1/4" of tread) has much less traction than a new tire. If my tires are getting very close to replacement time and winter's approaching, I replace them. Makes a world of difference.
Seriously...if you don't have a lot of practice sliding around on snow and ice, and you aren't comfortable with the idea - DON'T follow my approach - leave the traction control on. I don't wanna see someone get hurt trying something they're not comfortable/familiar with. But these cars CAN be driven in the snow just fine with a little skill, finesse, and experience. If you aren't comfortable yet, find an empty parking lot, and eventually some empty side streets where you aren't going to pile into other cars - moving OR parked - or pedestrians, and practice 'til you feel safe controlling the car through a 2 or 4 wheel drift on snow (at LOW speeds - 10, 15mph going into the turns). It's fun, and it's invaluable experience. Just try to avoid the eyes of the law. They frown on such learning experiences. And don't do what my brother (who has little experience horsing around in cars) did with his old Exploder. Don't put it into a drift in an empty lot, and notice too late that there's a light pole in the way. Sideways slides into lightpole bases can put SERIOUS wrinkles in your nice shiny car.
Of course, I learned how to handle a car in such conditions years ago, in my parents beater cars and my first beater cars...not in a nice several thousand dollar, 260 hp sporty car.
Or just park it. That's what lots of people do. (No fun in that, though.)