November 3, 2006 - If you want to play Sony Online Entertainment's http://ps3.ign.com/objects/814/814614.html against your buddies across the country, then you'll need to sign in to the PlayStation Network for sure. Until today, it was unknown if the game's online co-op feature would use SCE's proprietary online service in conjunction with the Xfire software, or if Xfire would power it on its own.
To put it in the simplest of ways, the Xfire functionality is a bonus addition to the existing PS Network setup (think of it as "AIM for Mages") and will allow its users to setup friends lists independent of an existing SCE-provided buddy list (and not in spite of it).
Sadly, we didn't get to test out the feature with much success as PlayStation 3 test units currently have their network compatibility features turned off. But at least the world now knows for sure how Dark Kingdom is supposed to work.
Thanks to http://ps3.ign.com/articles/744/744047p1.html for sharing the news with us!