Hi, am brazilian married with a british man and we are currently living in UK and i recently got my first marriage Visa to live in UK for 2 years, but we are thinking to move down to Spain. Would like some advice what do i need to do to get NEW VISA to Spain or either CHANGE my UK Visa for a Spanish one. Any help will be much appreciated. Thanks

deva,
the spanish consulate can inform you better on requirements,
as far as i know, brazilians do not need visas to enter spain, but you would have to carry with you your alien card for the uk.
as far as i know you do not need visa to become a resident after your british husband registers as resident in spain.
uk visas are issued by uk consuls, spanish visas are issued by spanish consuls.