http://en.wikipedia.org/wiki/TransgenderTransgendered people may or may not have had medical gender reassignment therapy, and may or may not have any interest in such a procedure.
When referring to the two basic "directions" of transgender, the terms Transman for female-to-male (which may be further abbreviated to FtM) transgendered people and Transwoman for male-to-female (which may be further abbreviated to MtF) transgendered people are often used. In the past it had always been assumed that there were considerably more transwomen than transmen. However, the ratio is approaching 1:1.
Transgender can include a number of sub-categories, which, among others, include transsexuals, cross-dressers, transvestites, consciously androgynous people, drag kings and drag queens. Usually not included, because in most cases it is not a gender issue (although in practice the line can be hard to draw) are transvestic fetishists.
Many people also identify as plainly transgender, although they may fit the definition of any of the previously mentioned categories as well.