Here's another pain point for Research In Motion (RIMM): Dell is dumping 25,000 BlackBerry devices in favor of its own line of smart phones.

It makes sense. You gotta use what you're trying to sell. Eat your own dog food, as the tech world calls it.

But the last thing RIM needs right now is large-scale ship abandonments such as this one. Shares of the company were down 3% Friday on the news.

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And Dell (DELL) is pushing the stakes even higher. Not only is it moving its own employees off BlackBerrys, it's going to sell a service to help other companies do the same, reports Shayndi Raice at The Wall Street Journal.

"Clearly in this decision we are competing with RIM, because we're kicking them out," Dell's chief financial officer told the Journal.

 

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Dell is asking workers to use the Dell Venue Pro, an upcoming phone that runs the new Windows Phone 7 software from Microsoft(MSFT). In the future, Dell plans to let employees use phones with the Android software from Google (GOOG). (Microsoft publishes MSN Money.)

Dell says the move will help it save money, particularly as it shuts down the pricey servers needed to run BlackBerry phones. The company said it will soon offer business clients help doing the same thing. RIM scoffed at the notion, saying Dell probably won't save any money in booting up an entirely new system.

Consider this one more sign that RIM is losing its once iron-clad grip on the corporate market.

Apple (AAPL) has said half the companies in the Fortune 100 are using or testing its products. And with credible offerings for business users, Google and now Microsoft are making the field uncomfortably competitive for RIM.