The Product Manifesto - Product Managers face the biggest challenges of our day, which is why our community needs a common set of product principles.
Product School - The global leader in product management training
The Product Management guide - A book on how to create and ship products that people love
PM Starter Pack - Practical guide on how to get started in product management
Nifty - Manage projects, work, and communications in one place.
Software Product Management Stack - Resources & tools to help you manage your software product