The term Transgendered is actually a universal term that encapsulates all the trans community. This includes:
Transsexuals - Men and women who feel they are the opposite gender then that assigned at birth. They often have dysphoria toward their bodies and seek to be the Identifying gender full time. This is a medical condition believed to happen within the first trimester when they fetus changes gender. Some transsexuals may go through more extreme dysphoria and multiple surgeries, where as some just feel the need to dress as their identifying gender. Most transsexuals now they are the wrong gender at a very young age ( for instance I told my mom I was a girl when i was 2)
Transvestites - Men and women that dress in the opposite genders clothing for sexual pleasure and or arrousal. Also refered to as Fetish Dressers.
Crossdressers - Men or women that dress in womens clothing as a way of self expression or for fun
Drag Performers - Men or Women that dress as the oposite gender as a way to entertain people.
Genderqueer - people that feel they dont fit either gender
Androgynous People - People who like to exbit both genders in their fashion and look so they appear both female and male
Bigendered - People who feel they are both genders and use different genders to do different things. Most bigendered people pass as male and female and use each gender for specific things in Life. Such as Date as A man, Work as a female, see family as a Man, Have sex as a female. This form of transgender is the rarest affecting less then 3% of the trans community.
Ok I think I got most. Basically gender is a huge confusing thing and shouldn't be categorized into two little boxes. I learned all this Volunteering at the pride center for trans youth!
Hope that Helps!