WWDC 2011 videos session can be downloaded if you have a developer account. For developers who weren't at the WWDC (like me) It's a great opportunity to learn many things.

I watched all the videos I was interested in, and I was pleased to see that in session 105 (Polishing your app) two things that I've recently talk about were evoked :

• Rate this app alerts are bad, nothing more to say, really. At 11' in the video.

• Synchronous NSURLConnection are bad, really. At 18'10 in the video.

If you want to learn about the new ARC (Automatic Reference Counting) feature, watch these videos :

• Session 323 – Introducing Automatic Reference Counting

• Session 322 – Objective-C Advancements in Depth

For improving your apps performances :

• Session 310 – What's New In Instruments

• Session 312 – iOS Performance and Power Optimization with Instruments

• Session 318 – iOS Performance in Depth

• Session 121 – Understanding UIKit Rendering

Core Graphics (Quartz) is easy :

• Session 129 – Practical Drawing for iOS Developers

Of course there are plenty more on a wide variety of subject that you should definitively watch.