Other resources

Templates
http://www.getappninja.com/

Dealing with documents
http://developer.apple.com/library/mac/#documentation/DataManagement/Conceptual/DocBasedAppProgrammingGuideForOSX/Designing/Designing.html

http://developer.apple.com/library/mac/#documentation/cocoa/Conceptual/CoreData/cdProgrammingGuide.html

Push Notification
http://developer.apple.com/library/mac/#documentation/NetworkingInternet/Conceptual/RemoteNotificationsPG/ApplePushService/ApplePushService.html