It seems that Apple's new Ping service and Facebook are not currently on the best of terms. Facebook Connect integration has been removed from Ping after Facebook denied the connection due to Facebook's policy that any service that wants to hit their friend-finding API an extreme amount of times has to sign a deal agreeing to limit network impact and protect Facebook's user data.

Apple and Facebook never had a deal in place for this service when Ping was launched because negations broke down due to what Steve Jobs dubbed "onerous terms," but Apple used the API anyways until Facebook blocked access. Rumor is that the two companies are still negotiating to get the services to play nicely with one another, so this may only be a temporary disconnection.