WHERE
To find an immigration doctor in your area you can check here.
WHAT DO YOU NEED
Make sure you bring you vaccine record(s) to prove you have all the mandatory vaccines (a list can be found here). If you don't have them, or if you don't have proof of having them, you will need to get them and pay for all of them. They also check your blood pressure, listen your heart and lungs, look at your eyes and ears.
Next, they draw some blood to check a few things (among them the chickenpox teeter, so if you have proof you had the chicken pox you may want to give it to them). The more blood they draw, the more you pay. So anything you have or had, bring documentation and show them because my experience was that they do not ask for anything - they just take the blood samples and pass you the bill.
Finally, you pay and go home (they may have you pay, then get the blood drawn, and then go home). The following is a breakdown of the costs I payed as of 2011 per a North Carolina immigration doctor.
-Physical exam $150
-RPR (STS) $20
-QuantiFERON-TB Gold $60
-Varicella Teeter $30
With a total of $260, out of the $350 we expected after our research.
About 10 days later you will receive a copy of the completed paperwork for you, and a sealed envelope (not to be open) to be sent to USCIS with the other paperwork.
Updated January 2017