For the rotating an object by center by touch in iPhone

https://github.com/hollance/MHRotaryKnob
http://rdsquared.wordpress.com/

For the different kind of demo for iPhone

http://stackoverflow.com/questions/1939/how-to-articles-for-iphone-development-and-objective-c

For the Encryption and decryption of the url

http://blog.objectgraph.com/index.php/2010/04/20/encrypting-decrypting-base64-encode-decode-in-iphone-objective-c/

For the barcode url parsing

http://searchupc.com/developers/login.aspx

For the emoji icons

http://arashnorouzi.wordpress.com/

For .Net push notifications

https://github.com/arashnorouzi/Moon-APNS

For the Cocos2d game example

http://mobile.tutsplus.com/tutorials/iphone/learn-ios-game-development-by-example-10-projects-to-get-you-started/