Cydia - An alternative app store for jailbroken devices.
Product School - The global leader in product management training
AppRecs - AppRecs sorts through reviews in the App Store and automatically helps you filter out inauthentic results.
The Product Manifesto - Product Managers face the biggest challenges of our day, which is why our community needs a common set of product principles.
Fnd - Browse Apple App Store and iTunes on the Web
Intercom on Product Management - The ultimate resource for aspiring product managers