Pretty good summary article charting the last couple of years that led up to the arrest, release, and careful monitoring of the comings and goings of China's most high-profile, though self-admittedly most lucky (privileged?), dissident (a term Ai, in fact, disavows). Beyond summarizing key events and facts, the article is full of informative links to follow, including a thoughtful musing from Ian Johnson at the The New York Review of Books, on the somewhat schizophrenic state of freedom in Chinese society, ranging from house arrests and kidnappings of human rights lawyers, to the all but unrestricted rights of most upwardly mobile Chinese commoners. For more information on other imprisoned dissidents, you can start here.
http://www.guardian.co.uk/artanddesign/2011/nov/26/ai-weiwei-china-situation-quite-bad