As with any plan to move to another country, it is imperative that you learn the language of that country.  While Spanish has become quite universal, the Spanish spoken in Spain is different than the Spanish spoken in North or South America. 

Spanish and Castilian are the primary languages of Spain.  Castilian is recognized as the official pronunciation of Spain’s Spanish language.  It is spoken by television spokespeople, newscasters and all of official Spain.  Castilian is the national Spanish language.  Castilian has a specific sound to its spoken language that separates it from Spanish.  Listen well, and learn to speak Castilian Spanish. 

When looking for a Spanish language instructor, specifically request someone who speaks Castilian.  Find language tapes, or CDs, preferably from an instructor from Madrid or Barcelona, if you want to avoid local accents and dialects.

Immersion is the best language instructor.  You can wait until you have relocated, or you can home-study prior to your move.  Turn on a Spanish TV channel, even if it’s not Castilian Spanish.  It is still Spanish and you will be learning as you listen.