The social gaming market on the iPhone has taken two sharp turns recently. First up, right after announcing that their system hit a full million users, OpenFeint announced that their social gaming platform has gone completely free for developers. Originally, the SDK was free to download, and then there was a small cost-per-user fee for developers, but with this new change, that cost is gone, and OpenFeint will now make all of their money, as we were told by Peter Relan, from referring users to other games and in-app purchases, and then taking that cut from Apple.
The popular publisher Chillingo has also announced a newcomer to the social gaming scene: they're planning to introduce another system called Crystal SDK, that will presumably both be free to all developers, and automatically included in most of Chillingo's games. Their release specifically tells us that "Crystal is iPhone's answer to Microsoft's Xbox Live," so they're officially throwing their hat in an already crowded ring.
With a million users, OpenFeint is still the biggest network going, but obviously Chillingo believes there's still many more to pick up. Should be interesting to see, as always, what users decide to do.