Found these screenshots recently from the rumors forum at www.star-craft-2.com...not sure if they're real (kinda look like half-life mod) but they're sweet anyway.
Aight after lookin' at these for about 5 minutes I noticed a couple things: first and most obviously, the game's a first person shooter probably from the point of view of a marine. Life bar is at the top, radar at top left, minerals (money?) at top right, stim/ammo at bottom left, and targetted creature portrait in bottom right. I still haven't figured out what the red arrow at left of screen or the white pellets at the right are for, if you find out, well, that's good for you.