I stumbled into a wonderful website, VIARTIS, which provides summaries of up-to-date news, research and books about Parkinson's Disease. I particularly appreciate that it is written in easy-to-understand language.
Take a look at Viartis' Parkinson's Disease News at: http://viartis.net/parkinsons.disease/news.htm. Also review the Archives (at the bottom of the page) which has articles archived by month from July 2007 to the present.
From their website:
Viartis are independent and entirely self funded medical researchers specialising in Parkinson's Disease, based in London, England. Viartis are not part of any other company, university or organisation, and have no religious or political allegiances. Articles are chosen solely on the basis of their medical significance or potential interest. The overwhelming priority is the facts, regardless of whether or not they contradict prevailing views or vested interests. Analysis of some articles is provided either to explain the background or implications of new information, or to balance any misleading claims. This web site is entirely free and non-commercial. It contains no adverts. Nothing can be bought directly from this web site. It does not receive payments from linking to any other web sites. This web site is viewed by many thousands of people in over a hundred countries all over the world.