Google has a published a new Webmaster Help video, in that Matt Cutts talks about buying domains that have had trouble with Google in the past, and what to do.
Matt Cutts responds to the question:
How can we check to see if a domain (bought from a registrar) was previously in trouble with Google? I recently bought, and unbeknownst to me the domain isn’t being indexed and I’ve had to do a reconsideration request. How could I have prevented?