This is nearly an unprecedented move and quite the boast for Microsoft but Dell just announced that it will be switching 25,000 of their employees from their RIM BlackBerrys to their own Venue Pro running Windows Phone 7. Eventually they'll also offer Android devices as well. No punches were pulled either as Dell CFO Brian Gladden told the Wall Street Journal:

Clearly in this decision we are competing with RIM, because we're kicking them out...

The change will begin next Wednesday and the move  is expected to save the company 25% in communication costs over the long term. Not only are they doing this internally, but Dell is setting up a service in 2 weeks to help other companies transition from RIM to alternative OS providers as well. Presumably that would Windows Phone 7, since Microsoft's Exchange system is quite widely adopted, robust and cheaper than RIM.

This news is huge and could be the beginning of the decline of RIM in the business market.

Source: WSJ