Plus+ was one of the first social network services available to iPhone gamers from Ngmoco, so they were one of the first developers we reached out to for a reaction to . Reached via email, Ngmoco president Simon Jeffrey said that Game Center will "effectively clean up the social space on the iPhone, which has become confusing and cluttered to consumers due to the number of social gaming networks vying for attention."

Jeffrey said that Ngmoco anticipated something like Game Center coming from Apple a long time ago, and that the company's successfully evolved Plus+ into a service that complements Game Center rather than competing with it.

"As we demonstrated at the recent GDC, plus+ took a strategic shift in direction a few months ago toward being a service, and less about being a set of social gaming features," he said. "Plus+ is all about empowering monetization and discoverability mechanisms for the development community, and we have clearly demonstrated with games like We Rule that these mechanisms work."

We've reached out to other iPhone developers like Chillingo and Gameloft to find out how (and if) they plan to adapt their online gaming network services to Game Center. We'll update this post as the story develops.