Here are the collection of snippets to do CRUD operation with ZKSforce (Force.com toolkit for iOS).
Remember this is a SOAP based API, there is a new alternative library available from salesforce called MobileSDK for iOS.
Update (2016-01-20): The app is now available on Mac App store.
Additional menu clock for your Mac. A minimalist clock to display time of different timezone of your choice.
Until recently I was not aware of the shortcut _Ctrl + Cmd + C _
It captures the complete content of the iPad simulator to the clipboard, You can save it to a file by File -> New from Clipboard with preview.
A quick obj-c cheat-sheet for the beginners.
Scribd link
This is taken from RWTH-iPhone Application Programming. You can also download complete videos from iTunesU.