The vast majority of forensic-fellowship trained psychiatrists work in correctional settings (either as employees or independent contractors), and some of them attempt to develop a forensic consulting private practice on the side (for expert witness type testimony, or consulting on capacity issues, disability issues, custody issues, malpractice issues, and other forensic psych/legal interface issues, for either individuals or for organizations).
Correctional settings are pretty tough. The pathology is, I guess, interesting. The $$$, if you are an employee of a county or state (in a correctional setting) is less than one would make in pure private practice, but the $$$ made OUTSIDE the correctional setting, as a a forensic psych. consultant, is theoretically much better than regular private practice general psych. reimbursement. Obviously, for your forensic consulting private practice to suceed and become profitable, and self-sustaining, you have to have a good business sense, learn to network with the other major players of the legal system (lawyers), and have a specific interest and aptitude in such business and legal matters.
Some interesting books to read are:
Dr. T. Gutheil's: The Psychiatrist as Expert Witness, The Psychiatrist in Court, and Clinical Handbook of Psychiatry and the Law.
Here's a link to the American Academy of Psychiatry and the Law