TUAW's also got the lowdown on code suggesting support for XMPP, the protocol that underpins Jabber, and most famously, Google Talk. It seems that access to the XMPP framework is being kept solidly out of third-party developers' hands, though, meaning that Apple -- and Apple alone -- will be using it to support on-device iPhone chat. At this point, both of these features need to be quarantined in the "rumor" category, because even if the code does exist as TUAW's tipsters are claiming, there's certainly no guarantee it'll make the cut for firmware 2.0, iPhone 2, iPhone 3, or iPhone 10. Looks promising, though!
Read - iControl
Read - Jabber support