If you are in the United States - it will be based on state law. You can probably do a yahoo or google search and come up with your state's statutes and look up the licensing requirements and penalties.
For example:
ALABAMA STATUTES AND CODES

Section 34-26-42 Penalty for unlicensed person held out to public as psychologist or psychological technician.
Section 34-26-42
Penalty for unlicensed person held out to public as psychologist or psychological technician.

If any person holds himself or herself out to the public as being engaged in practice as a psychologist or psychological technician, such as clinical, counseling, school, or combined professional-scientific psychology, and does not then possess in full force and virtue a valid license to practice as a psychologist or psychological technician under this chapter, he or she shall be deemed guilty of a Class C misdemeanor and, upon conviction, shall be fined not less than one hundred dollars ($100) nor more than five hundred dollars ($500). Nothing in this chapter shall be construed to limit the professional pursuits of teachers in recognized public and private schools, clergymen, practitioners of medicine, social workers and guidance counselors from full performance of their professional duties. However, in such performance any title shall be in accord with this chapter. Students of psychology, psychological interns, or other persons preparing for the profession of psychology may perform as a part of their training the functions specified in this chapter, but only under qualified supervision. Use of psychological techniques by business and industrial organizations for employment placement, evaluation, promotion, or job adjustment of their own officers or employees or by employment agencies for the evaluation of their own clients prior to recommendations for employment is also specifically allowed. However, no industrial or business firm or corporation may sell or offer to the public or to other firms or corporations for remuneration any psychological services as specified in this chapter unless the services are performed or supervised by individuals duly and appropriately licensed under this chapter.

(Acts 1963, No. 535, p. 1147, §6; Acts 1997, No. 97-387, p. 619, §3; Act 98-146, p. 230, §3.)

or Wyoming:
33-27-119. Practice without license.

(a) Repealed By Laws 2009, Ch. 154, 2.

(b) Unless exempt under W.S. 33-27-114, any person who represents himself as a psychologist and who engages in the practice of psychology in violation of this act, is guilty of a misdemeanor punishable by a fine of not more that seven hundred fifty dollars ($750.00), imprisonment for not more than six (6) months, or both. Each violation shall constitute a separate offense.

(c) Any person filing or attempting to file as his own, a diploma or license of another or a forged affidavit of identification shall be guilty of a felony and shall be subject to the punishment prescribed for forgery under W.S. 6-3-602.

(d) No person whose license to practice as a psychologist in any jurisdiction has been suspended or revoked shall practice psychology in this state. The board may suspend or revoke the license of that person. The board may issue a new license whenever it deems the issuance to be safe and just.

(e) The board on its own motion may investigate any evidence or allegation that appears to show that any person is or may be in violation of any provision of this act.

(note this was just a random search I did on yahoo for state codes/statutes. Usually I go to the state govt. page and get the statutes from there. I am not saying these are the most current statutes in these states.)