If you have not been to LinkedIn Answers, you should check it out – it has a great section on product management. There is a wealth of information there on market research, pricing, product positioning and a ton of other stuff. Have a question? post it there for free and get answers from LinkedIn members from all over the world. Even just reading the answers to the posted questions will give you a lot of food for thought. I use it as a great resource of reading material and also answer questions. By answering questions, you are also building your brand as a product manager !