- objc.io - once a month in-depth technical topics related to Objective-C, by Chris Eidhof, Daniel Eggert, and Florian Kugler. A must read for everyone that is interested in best practices and advanced techniques.
- NSHipster - another high quality resource on topics for Objective-C, by Mattt Thompson.
- NSScreencast - weekly screencast on iOS development, by Ben Scheirman. This is a paid subscription-based service.
- iosdevweekly - weekly emails of iOS development links, by Dave Verwer.
- Ray's Monthly Newsletter - monthly tutorials for iOS developers and gamers, by Ray Wenderlich.
- Evolution or Extinction - weekly newsletter on iOS and other technology topics, by my good friend and co-worker Justin Kent.
Subscribe, read/watch, and enjoy!