According to SEO Roundtable, Google has confirmed the only way for a site that has been affected by it's Penguin algorithm (which checks for low quality and dodgy link practices) is to sit and wait for it to re-run the next Penguin update.
Currently the last one was just over 11 months ago, so any sites that were hot and have cleaned up their act, are now sat patiently waiting.
Rumour of a new Penguin roll out keep circulating, but there is nothing official as yet from Google.
Full story: Recovering From Penguin Requires An Algorithm Refresh - SEO Roundtable
It seems Panda updates seem to get rolled out a lot more frequently, although the last Panda update was last May, so no doubt it's time for a new one!
