A while back when there was an official group on fb for Treehouse I started a doc to compile useful links for iOS dev.
List of useful iOS tutorials/blogs, apps etc
Apple
http://developer.apple.com/library/ios/navigation/
Treehouse
http://teamtreehouse.com/library/ios-4-foundations
http://teamtreehouse.com/library/ios-5-foundations
[Think Vitamin http://membership.thinkvitamin.com/library/ios-development]
iOS Dev Weekly
[http://shinydevelopment.com/]
Google API
http://code.google.com/p/google-api-objectivec-client/
-------- | VIDEOS | --------
Stanford iTunes U
http://www.stanford.edu/class/cs193p/cgi-bin/drupal/
Fall 11
http://itunes.apple.com/itunes-u/ipad-iphone-application-development/id473757255
Winter 10
http://itunes.apple.com/us/itunes-u/iphone-application-development/id384233225
Fall 10
http://itunes.apple.com/us/itunes-u/developing-apps-for-ios-hd/id395605774
http://itunes.apple.com/us/itunes-u/developing-apps-for-ios-sd/id395631522
----------- | TUTORIALS | -----------
Ray Wenderlich
http://www.raywenderlich.com/tutorials
http://www.raywenderlich.com/store
Marin Todorov
http://www.touch-code-magazine.com/
Mike Rundle
Matt Gallagher
Steffen Itterheim
Mohammad Azam
http://www.highoncoding.com/Categories/37_Mobile_Development.aspx
They do a Podcast together
http://cocos2dpodcast.wordpress.com/
TutsPlus - Mobile
http://mobile.tutsplus.com/?s=ios
The New Boston
Objective-C
http://www.thenewboston.com/?cat=38&pOpen=tutorial
iPhone Development
http://www.thenewboston.com/?cat=34&pOpen=tutorial
http://www.iphonesdkarticles.com/
Kickstarter
http://www.kickstarter.com/projects/eallam/try-ios-iphone-app-development-course
------- | CODE | -------
objclibs
BinPress
http://www.binpress.com/browse/objective-c
iPhone Gamekit
- http://iphonegamekit.com/game-source-code/cocos2d-iphone-rpg-engine/
- http://iphonegamekit.com/game-source-code/cocos2d-iphone-checkers-game/
- http://paralaxer.com/
CartoonSmart
http://www.cartoonsmart.com/iphone_index.php5
-------- | BOOKS | --------
C Programming Language 2nd Edition
http://www.amazon.com/C-Programming-Language-2nd-Edition/dp/0131103628
Programming in Objective-C 4th Edition
http://www.amazon.com/C-Programming-Language-2nd-Edition/dp/0131103628
Beginning iPhone 4 Development: Exploring the iOS SDK
http://www.amazon.com/Beginning-iPhone-Development-Exploring-iOS/dp/143023024X/
Learning iPhone Programming
http://www.amazon.co.uk/Learning-iPhone-Programming-Xcode-Store/dp/0596806434/
STY IPhone Application Development in 24 Hours
http://www.amazon.co.uk/Yourself-IPhone-Application-Development-Yourself/dp/0672332205/
Games
Learn iPhone and iPad cocos2d Game Development
http://www.apress.com/9781430233039
Learning Cocos2D
http://www.amazon.co.uk/gp/product/0321735625/
------ | APPS | ------
Status Magic
http://shinydevelopment.com/status-magic/
"Status Magic is an application for Mac OS X which adds perfect status bars to your iOS App Store screenshots."
Linguan [Localizing Strings]
http://www.cocoanetics.com/apps/linguan/
Dash [Snippet Manager, Documentation Browser] Charging now
http://itunes.apple.com/app/dash/id458034879?mt=12
iConify
http://itunes.apple.com/app/iconify/id416289784
[http://mugunthkumar.com/mac-apps/iconify/]
ShipIt
http://itunes.apple.com/app/shipit!/id492043869
Interface (for iOS) [$9.99]
http://interface2.lesscode.co.nz/
Accessorizer [Xcode 4 does this now.]
http://www.kevincallahan.org/software/whatsNew.html
For Games:
Tiled
Level Helper
Sprite Helper
Physics Editor
Texture Packer
Spriter
http://www.brashmonkey.com/spriter.htm
[http://www.kickstarter.com/projects/539087245/spriter]
Cocos Builder
Spriter
http://brashmonkey.com/spriter.htm
http://www.kickstarter.com/projects/539087245/spriter
--------------------------------------------------------------------------
-------------- | FRAMEWORKS | --------------
Tapku
Games
Cocos2d
http://www.cocos2d-iphone.org/
Corona
http://www.anscamobile.com/corona/
Unity
[https://www.facebook.com/groups/164031216987291/doc/180376772019402/]
