I am Oklahoma City metro area that has a population of about 1 million.The way most of my friends have started doing this is just making friends or a good impression on some attendings or even whole groups(eg the pulmonology group). They then offer to do or take care of their discharge summaries for them, usually for a flat rate. They then do the summaries; save the job numbers, and then mail them an itemized bill. Some docs take out $ for taxes, and some don't. I think (I am not a tax expert) you may not be required to pay/withold for 'contract' labor, eg you are not a regular employee.
The way I did it was really easy. I went to Kinko's, printed up some simple and cheap business cards with a little picture of a telephone (resembling a dictaphone) and my name, job title (OU Anesthesiology Resident) and had it say "Speedy Dictation Services-Getting behind, call me!". I took a bunch these cards and tactfully placed them in physician dictation areas in the ED, doc lounges, etc. I also handed a few of my cards directly to some of the docs. "Hey DrX, if you ever need help with your dictations, let me know!" I have several docs interested and some that have already told the hospital medical records dept to call me as soon as they have more dictations needed by him-he won't even call me-the hospital will! I have met other ladies from med records who have asked me for my cards, so they can give these to other doctors who are behind. And they are thrilled.
There are several residents in my own program who have done this since their intern year, although there is nothing saying any medical student couldn't do it either. As long as you know how, you can get the format from the inside of CCS Medicine, Ferri's Guide, or even the pocket Maxwell.
For example, I dictated about five the other day in about 2 hours of time. I billed the doc for $125. Not bad considering-I can do it while on call, no malpractice insurance, no medical license needed, no liability, etc. Go for it guys!