The rivalry between Microsoft and Apple is one of legend. The two firms battle in many major categories including computers, mobile phones, and music players. The rivalry between the two firms has grown to epic proportions and in some instances; employees at Microsoft have been discouraged from using competitor's offerings.

In June of 2009, Microsoft changed its corporate policy to stipulate that it would only cover employees cell phone bills as long as the employee used a Microsoft-powered device. That means that the employees using the iPhone or a Blackberry were no longer being reimbursed for their calls. Microsoft said the reason for the move was to save money.

The Wall Street Journal reports that despite the fact that Microsoft workers using iPhones is frowned upon, many of them still use the Apple smartphone. The use of the iPhone is reportedly not hidden or uncommon at Microsoft's Seattle campus. Workers use the device openly in cafeterias and other locations reports the WSJ. According to reports, nearly 10,000 Microsoft workers are accessing the Microsoft employee email system using the iPhone. That number represents 10% of the firm's global workforce.

Microsoft executives have tried to spin employee use of the iPhone and other competitor's offerings. Microsoft's Andy Lees and Robbie Bach stated at a question and answer even that Microsoft workers often used a competitor's product to understand the competition. Microsoft COO Kevin turner also denied that he discouraged sales staff from using the iPhone. Turner stated, "What's good for the field is good for Redmond," according to one Q&A attendee.

There seems to be some that are uncomfortable using competitor's products at Microsoft. The WSJ reports that one person told the publication that some workers try to disguise their iPhone with generic cases. Some workers are also hesitant to use non-Microsoft devices in front of executives.

Despite the healthy rivalry, there are reports that Apple and Microsoft are teaming up against a common foe. Such is the case with the two firms reportedly in talks to see Bing search replace Google search on the iPhone.