The poll is multiple choice, and you can check all the ones that apply (i.e. if you're interested in all three, check all three).
Examples of two of the sorts of images they might present are these early sketches (which would be inked and fully colored by production time):
Prince Benedict of Amber
Whiskeyjack of the Malazan Bridgeburners
The latter has been created in consultation with Steven Erikson, and has received his approval.
ETA: I should add that Linda and I have gotten a sneak peek at some of the proposed images for the Ice and Fire prints, and they will likely knock the socks of quite a number of you off. ;)
Extra edit: There is now a second poll with more questions, found here. Please vote in that one too!
Edited by Ran, 30 November 2007 - 12:50 PM.