SISTRIX, a German-based SEO tools company, launched a Google Updates history page where you can track all the major Google updates in one place.
Both provide date information, with the name or type of the update that was believed to have happened. SISTRIX will also link to more details, when they have it, from studies they’ve published about the update. SEOmoz will also do something similar but they also link to outside sources with more details about those updates.
One thing this tool does that none other do is the ability to plug in your own URL and the tool will tell you how your site did after the update. For example, you can see the slight improvement this site had after a specific Penguin update:
Of course, there are plenty of places to track Google updates in text form and a less graphical way. Over here at Search Engine Land you can see all the Panda updates, Penguin updates, EMD updates, Pirate updates and Top Heavy updates as well as many more. And I publish almost every little change at the Search Engine Roundtable in the Google updates category.
Having these more graphical looks at Google updates that are maintain by the SEO toolset provides often comes in handy for many SEOs.