I have collected a lot of links over the last year+ to various blogs and tutorials that have helped me learn how to get started with iOS development. I'll try to keep a running list of the most helpful ones here, both to help others get started and give credit where credit is due. Please pay them a visit and click on an ad or two...most of these guys/gals are doing this stuff for free.
http://www.raywenderlich.com/ - Superb place to start if you want to make apps or games with cocos2d. This guy has so many tutorials, I myself have barely scratched the surface. His wife also has a sister site with art and art tutorials, at http://www.vickiwenderlich.com/.
http://www.stanford.edu/class/cs193p/cgi-bin/drupal/downloads-2010-fall - This page has all the downloads for the iTunesU Stanford class on iOS programming. Everyone should know that Stanford offers this class in iOS development and puts the whole thing online for FREE! I'm still amazed that they do this, and wish I had more time in my week to 'take' this class.
http://www.cocoalab.com/?q=becomeanxcoder - This site has a nice overview of Objective-C targeted towards us using Xcode and cocoa. Great starting point and quick refresher.
http://cocoadevcentral.com/d/learn_objectivec/ - Another one page overview of Objective-C that can be useful as a reference or starting point.
http://www.cocoanetics.com/ - Oliver is awesome on twitter (@cocoanetics) and does a lot to promote and help other developers. I haven't delved into his website so much, but he's so helpful on twitter I had to link him.
http://thinkultimate.com/2009/10/iphone-screen-capture/ - Here's a simple tool/plugin that captures video on the iOS Simulator. Great for making demo videos of your apps/games.
http://ganbarugames.com/2011/07/cocos2d-game-center/ - I love this guy's blog, and this post specifically helped me...ok, completely told me how to get Game Center up and running in quadropong. Great stuff here.
http://thirdcog.eu/apps/cfxr - cfxr is a noise maker app that is perfect for that 8-bit, chip tune style sound effect in your game. It's fun to play around with the randomly generated sounds, and is fully tunable and adjustable so you can get it just right.
I also follow a lot of developers on twitter, and I was going to make a list of the most helpful/interesting ones, but that seemed a little...stupid. It would be much easier for you to just go to my profile (@jonnysuave), see who I follow, and pick out the developers (shouldn't be too hard). And while you're there, go ahead and follow me too.
