Google's Matt Cutts tweeted that they have launched a form to submit to Google if you think your site should not have been hit by the Penguin update.
With Panda, Google did a similar thing about a week or so later, but made people post the details in a forum support thread. That thread had almost 10,000 posts before it died during the forum migration.
So this time, Google opened a basic form that feeds to a Google Spreadsheet where Googlers can review the sites and make changes the the Penguin update.
Here is a picture of the form:
To access the form, click here.
Forum discussion at Twitter and Google+.
Image credit to ShutterStock for Penguin with pencil