:) Hi, my name is Tasha and I am 14 years old. My life at home isn't so good.My aunt has invited me to come live with her in Houston Texas. What are the steps for her to gain custody of me? Also how would I go about getting a student visa ?

Well she dosen't have to have custody for you to live with her, only permishion from your parents. If they won't give it you are probably out of luck. (for now) Unless your parents are unfit, to care for you the court is not going to give "custody" away. They may however allow you to go live there. A student visa can be obtained here

Student Visas (http://travel.state.gov/visa/temp/types/types_1268.html)
UnitedStatesVisas.gov -- Studying in the U.S. (http://www.unitedstatesvisas.gov/studying.html)
Students - Visas & Immigration (http://www.immi.gov.au/students/)
These are just to get you started it depends on where you want to go

I will assume you don't live in the US, so you will need a visa?

But basically you will have to havev your parents to OK it,

Since you are living outside the US, US courts would not be able to award custody and since aunt is not in your nation, they would not have authority

If you parents agree to get you a student visa and meet all passport requirements you do not need transfer of custody. However. Once you reach Texas your aunt will not have legal authority and responsibility over you. If you needed a doctor or hospitalization she would not be able to sign permission for treatment.