Here’s an addictive combination: Facebook on your BlackBerry.

Facebook co-founder Dustin Moskovitz kicked off the second day of the Cellular Telecommunications Industry Association conference in San Francisco by announcing a deal that puts the social networking site’s features on Research in Motion’s (RIMM) BlackBerry smartphones.

Facebook will come with new T-Mobile BlackBerry smartphones and will be available as a download for BlackBerrys from other wireless carriers. The application will allow BlackBerry users to access most of Facebook’s core features, like tagging and uploading photos to their profile pages, updating status messages, and viewing friends’ Facebook activity.

“We finally found a team that we felt shared our philosophy and vision for mobile social networking,” Moskovitz, Facebook’s vice president of engineerin, told conference-goers Wednesday.

RIM co-CEO Mike Lazaridis joined Moskovitz on stage to demo the new application. “Within two days, we had the first working prototype,” Lazaridis said. “We were able to use the two open platforms and start intimately linking them together.”

Some Facebook features were previously accessible on mobile devices but this is the first time that the social network has been directly integrated into a phone’s software. Facebook will be available as a download for any carrier later today at www.facebook.com.

The 23-year old Moskovitz also took the opportunity to tell wireless carriers that open mobile platforms are the future and they better adapt by unlocking their operating systems and hardware. Currently most mobile devices are pre-programmed to only function on one carrier and not all operating systems are open to third-party developers.

“Two companies are going to force the next step forward,” he said. Apple, by allowing third-party developers to build on top of the iPhone, and Google. Of Google, which is rumored to be both developing its own phone and negotiating to buy a piece of Facebook, he said, “it’s going to be big and it’s going to be open.”

Using Facebook’s open platform as a model, Moskovitz gave the crowd advice on how to build mobile platforms for the future: Let developers extend it and make it easy for them to profit from their applications.

“This means you have to be okay with leaving some money on the table,” he said.

That might a hard sell for the carriers, given that they raked in $10.5 billion in revenue from data services in the first half of the year.