Everyone's already said it, but between 100 and 200$ depending on what state your from. You can just google something along the lines of "(your state) corp filing form" and it should pop up, fill the forms out, and mail them in.

You most likely want to register as an "S-Corp" as opposed to a C-corp for tax purposes.

If you live in NY, you probably don't want an LLC either due to the required advertising in print publications. I'm not sure if other states have this, it could be just NY. http://www.yourincorporation.com/lawbrary/publication-requir...