tedster - 4:25 pm on Feb 13, 2010 (gmt 0)
It is common among those who inject parasite content that they also point many backlinks to those pages. Have you checked for that kind of thing?
Also, if you haven't already, I'd suggest using Webmaster Tools, and particularly the "Fetch as googlebot" function. Once a server has been compromised, there may well be spam on the pages that is cloaked for googlebot, and this is a helpful utility for spotting that.