How do I get started with Mindstorms NXT 2.0? I need help programming a NXT 2.0 Lego Mindstorms. I want to make the robot turn, stop, go back, etc. when the color sensors see certain colors. For example when the robot sees red it stops then turns. Please help me I am new to Mindstorms and programming.
As was pointed out, this question is not specific in nature, so it's hard to give a definitive answer. If you haven't already done so, it would probably be helpful head over to Lego.com and grab get the NXT 2.0 User Guide and perhaps begin looking through the sample programs.

This book may also be helpful to you:

The LEGO MINDSTORMS NXT 2.0 Discovery Book: A Beginner's Guide to Building and Programming Robots

If you run into specific problems as you are getting started, feel free to create a new question, and we'll try to help you out.