Does the sexual harassment law apply where the harasser is the same sex as the victim?

Yes.  The Supreme Court decided on March 4, 1998, in a case entitled Oncale v. Sundowner Offshore Services, Inc., No. 96-568, 1998 U.S. LEXIS 1599 *3 (Mar. 4, 1998), that "Title VII's prohibition of discrimination 'because of sex' protects men as well as women."  This protection extends to both men and women in "quid pro quo" sexual harassment and "hostile work environment" harassment where the harasser is of the opposite sex or the same sex.