http://en.wikipedia.org/wiki/Transsexualism

Wikipedia is definitely useful, but not entirely reliable. If you search 'transexualism' on Wikipedia, a brief definition of transexualism, information on diagnosis, origins, relation to gender roles, relation to transgenderism, causes, therapy, legal and social aspects and traditions comes up.  They pretty much have all the basic information that we want. However, the fact that anyone could post anything makes these information less accurate and unreliable.

http://www.indianwomenshealth.com/Transexualism-190.aspx

This website is designed and managed by a company called BioQuest Solutions. Their specialities are Medical content management, Marketing support, Clinical research, Direct marketing,, Digital marketing, Web-based applications etc. Definition of transexualism, cause of transexualism, symptoms of transexualism in children and adults, and treatments are listed. Information on the website is based on their research so
I feel that it's reliable.