Mass Effect 2 - Preview @ Cheat Code Central

Cheat Code Central talked to Casey Hudson, project director for the game, during Bioware's latest conference call. A summation of what they've learned can be found here. Nothing new really, except  maybe the part about exploration where Casey said that planets now have been made more interesting to explore. 

And this:

Also, rather than being tied to just one hub, The Citadel, players will be able to explore Omega. Omega is sort of The Citadel's antithesis. Instead of being the idyllic seat of galactic power, Omega is the Mos Eisley of the galaxy. In other words, it's the lawless, gang-ridden home of the galaxy's scum and villainy. In addition to a new major hub, players will also get to tramp around the Asari and Krogan homeworlds of Illyum and T'chonko (spellings were not clarified, sorry), respectively. Hudson made it clear that the depth and breadth of the narrative and setting are far more expansive.

A fair warning, though. The summation or preview does have a rather big spoiler at the end - nothing shocking to those who've followed the making of the game, though.