The first step would be to take apart the phone and find the part number of the camera module, from that you can locate the data sheet. However, I will warn you. The camera module doesn't do it's own processing so you will need to have a board able to do basic DSP operations. If you are doing this to save money, I would look elsewhere as you are almost certainly going to have to have PCB boards made and assembled. If you are not set up to make your own boards is likely to cost around $500-600 in parts and supplies and take 30-50 hours of your time. That said if you are doing this as a fun project and want to continue knowing the cost. Update your answer with the model number of the Camera and I will do my best to help you.