iphone social networking sharing functionality sdks

I'm looking for an sdk that can be integrated into native iphone apps to add social networking sharing functionality.

I'm familiar with AddThis, but it doesn't look like they have anything specifically built for the iphone. Any i开发者_如何学JAVAdeas?

Thanks, ward

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Check this : http://www.addthis.com/help/ios-overview

AddThis has released an iOS Sdk

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There's OpenFeint and the forthcoming GameCenter in iPhone OS 4.