An asexual is a person who does not experience sexual attraction. Asexuality is an orientation, not to be confused with celibacy which is an action.
There is a lot of diversity among asexual people. Some do not have any sex drive some do but it does not point at a person. Some experience romantic attraction and some do not. Some lean toward being with a particular gender while some do not. Some are transgender but most are not.
AVEN - The online asexual community and definitive source on asexuality