I second what's been said -- there's no good guidebook on Antarctica. The best info I got for our trip was reading a bunch of trip reports (mainly on TA... very few recent ones here, other than mine).

In addition to the tips already mentioned (which I don't need to repeat except SHIP SIZE MATTERS), I'd strongly recommend an itinerary that also includes South Georgia... if you can afford it (both time and money). I'd also recommend closely looking at how many actual days of landings are on the itineraries when comparing cruises -- the number of days of the trip is exaggerated and padded, so count the true days of landings. Also, don't worry so much about one company versus the next in terms of the lectures and other on-board stuff; it's all the same, and you're there the landings.