INQ Mobile recently conducted a study to determine the most influential Twitter users of 2009. They have released the top 20 most influential for the U.K. and internationally. They measured influence across five categories including entertainment, music, politics, sport and technology. Here are the top 20 international influencers. Click over to INQ to read the U.K. top 20. Pete Cashmore – CEO Mashable P. Diddy – Entertainer Stephen Fry – Entertainer Oprah Winfrey – Entertainer Kim Kardashian – Entertainer Ellen DeGeneres...