Hey I'm a straight beginner and I want to start gaining knowledge. I just want some references or suggestion a guide line to develop apps for windows phone
After you begin developing your app, you may have more specific questions. To answer those I really recommend StackOverflow. Likely the question will already be answered there. If not, then it is easy to ask one, and the community there is very helpful.
To learn how to make apps for Windows Phone, I just started making one. When I ran into problems, I searched for articles, tutorials, ect to fix them, and continued. After that first app, creating future ones became much easier.
Sorry to be the late-comer to the party, but one of the resources that I really do enjoy is IT eBooks - Free Download - Big Library. They have all kinds of IT related eBooks there that you can download in PDF version for free.