[iOS] Game Center

Game Center for Developers
Game Kit Programming Guide

iOS SDK: Game Center Achievements and Leaderboards - Part1
iOS SDK: Game Center Achievements and Leaderboards - Part2

How To Make A Simple Multiplayer Game with Game Center Tutorial: Part 1/2
How To Make A Simple Multiplayer Game with Game Center Tutorial: Part 2/2

Game Center memory deallocation (with Cocos2D)
Game Center memory leak

[iOS] iOS App Programming Guide

iOS App Programming Guide
UIApplication Class Reference
UIDevice Class Reference

Delegates for enter foreground and background

Disable Lock Screen:
[UIApplication sharedApplication].idleTimerDisabled = NO;

[iOS] Notification

Notification Programming Topics
Local and Push Notification Programming Guide
Local Notification

iPhone Development 101

[iOS] AVFoundation Programming Guide

AVFoundation Programming Guide

[iOS] TableView refresh by pulling down

PullToRefresh
EGOTableViewPullRefresh

[iOS] UIActivityIndicatorView

MBProgressHUD
SVProgressHUD

[iOS] Download, Create and Display an image from URL

Download, Create and Display an image from URL
Download an image and Save it as PNG or JPEG in iPhone SDK