The Wall Street Journal is reporting that in the last 18 months, Apple has hired at least five employees of the RIM enterprise team. They also speculate that there are many more employees that have, or are considering, jumping ship. Some of the employees that left RIM includes the Head of Strategy Sales who is now Head of Enterprise iPhone Sales at Apple. With over 80% of Fortune 500 companies trialling or using iPhones, there’s little doubt that Apple is gearing for a huge battle in the enterprise sector. The latest release of iOS 4.2 is the best version yet for corporate integration, and with the iPad finally getting the popular iPhone OS 4 features, we can only imagine things will be heating up even more in the coming months.