As you may have heard Apples Object persistence framework "Core Data" will be available in the next version of the iPhone OS. Unfortunately, the details are still under NDA so it will be a while before iPhone specific information will be available. However, there are a several good sources of Mac desktop Cocoa Core Data information that will help you get a head start on what you need to know. These include:

Build a Core Data Application at Cocoa Dev Central is a good tutorial that walks you through the steps.

ADC Core Data Video Tutorial by Wolf Rentzsch is really good. The Mac OS X 10.4 UI will take you back in time but the content is really good and still applicable today.

The Mobile Orchard has a nice article with a couple other resources.

Of course Apple has a lot of information that is iPhone specific as well as more general Core Data resources.

And finally Core Data by Marcus S. Zarra is a must have for anyone interested in learning the Core Data framework. The book is currently in Beta form but I am really glad I read it and it has saved me a ton of time already. It is targeted at desktop Cocoa developers but iPhone developers will get a lot out of it. All throughout the book topics are explained in plain English with practical advice for your various options.

What other resources do you know about? Let me know.