Matt Cutts has posted a link http://bit.ly/penguinspamreport where you can report web spam issues that you see in search results. This is specifically for spam that is a result of the new Penguin 2.0 algorithm.
Google is very slow to react to spam pages and for that reason is one of the root causes of most spam that we see online today. The inability to remove sites quickly sends a direct message to spammers that they can create sites and get four plus weeks of top rankings for high value key terms. This results in loss of traffic to sites that deserve it and exposes Google search customers to vulnerable sites.
What message does this send to webmaster who do the right thing? It says that those dirty tactics work and if you want to compete then you have to do the same thing.
As soon as one spam site is removed the spammers have another one ready and ranking. Being proactive and removing the site quickly is the key to resolving this not waiting until it is factored into the next algorithm!