Useful Library for iOS Development
Hello World Application
Getting Started with iOS
SQLite Tutorial for beginners
Coding Convention for Objective C.
Useful for beginners
Tutorial for Push Notification
Tutorial for database interaction in iphone sdk
Zip Archive tutorial
What to use ???!!!
Very helpful PDF Documentation provided by Apple
This chapter provides examples of the sorts of linear and radial gradients you can create with Quartz, compares the two approaches you can take to painting gradients, and then shows how to use each opaque data type to create a gradient.
A very useful link for masking
Some Sample codes that might help you
Cocos2d Sprite Sheets (blinking animation)