Initialize Core Data With Default Data
I had nearly the same question a few months back, did quite a bit of searching to find a nice easy answer, failed to find it and eventually settled on a roll-your-own solution that took a bit more time than I would have hoped, but was at least very helpful in learning to understand Core Data.
Basically the solution was to write a little utility that parsed my source data (which for me is a comma-separated text file, parsed using the quite handy 'cCSVParse' library - http://michael.stapelberg.de/cCSVParse ) and inserted it into Core Data Managed Objects and then saved that off as a sqlite persistent store. Then the sqlite store(s) can be shipped with the app, and uploaded by the user when they buy more data.
You could write a conversion from plist (or whatever) into the core data representation within the app itself, but if the data is just going live out the rest of its days in some core data form, why not let your beefy dev box do the heavy lifting before you send the data to the user, instead of shipping the data to the phone and making it do the work?