In case you missed this a couple weeks ago:
Today, the Sunlight Foundation has unveiled a tool that will help us all with this work. “The tool is, essentially, an open-source plagiarism detection engine,” web developer Kaitlin Devine explained to me. It will scan any text (a news article, e.g.) and compare it with a corpus of press releases and Wikipedia entries. If it finds similar language, you’ll get a notification of a detected “churn” and you’ll be able to take a look at the two sources side by side. You can also use it to check Wikipedia entries for information that may have come from corporate press releases. The tool is based on a similar project released in the United Kingdom two years ago, which the Sunlight Foundation supported with a grant to make it open source. Churnalism will be available both on the website and as a browser extension. Its database of press releases includes those from EurekaAlert! in addition to PR Newswire, PR News Web, Fortune 500 companies, and government sources.