NSHipster is a curated resource for iOS and OS X developers that examines some of the “lesser known” or neglected aspects of not just the Objective-C language, but also Cocoa and its related API’s. It’s a side project of Mattt (sic) Thompson, the mobile lead at Heroku and also the creator of the phenomenally popular AFNetworking Objective-C framework, among his many other credits.
The site is new and still small, but each one of the currently available posts is pretty great. As anybody will tell you, the highest barrier to entry for learning to develop on the Apple platforms isn’t actually learning the Objective-C language, but learning the various API’s (Cocoa, UIKit, etc). NSHipster looks to do a really, really great job of exposing little nooks and crannies in Apple’s API’s that can make your life much, much easier.
Even though the link isn’t exposed on the site itself, NSHipster does have an RSS Feed that I found just by looking at the page’s HTML in Web Inspector.