Ivy Bridge is just the "tock" of Sandy Bridge - a die shrink with a few tweaks - so it's pretty much the same architecture, so it'll come out in socket 1155 packages.
The question is though, if socket 2011 isn't due until Q3 this year, and Ivy Bridge is due Q1 2012, will we actually see Sandy Bridge on socket 2011, or just jump straight to Ivy Bridge?