getting set up as an independent contractor

I have been working for several months now for a rather large company doing product photography and photoshop work. I was hired basiclly as a temp but my supervisors have requested that I set my self up as an independent contractor. Since no longer working as a temp means a signifigant increase in my earning I am certain that this is what I want to do, but where do i start. Is it as simple as having a bank acount a tax id #, and keeping up with my own taxes? How should the paper work be handled, di I just produce a professional looking invoice for my time and costs. Do I have to have a Doing Business as id. If any one could give me some advice or point me in a direction that might help it would be greatly apriciated.

Thanks