if you havent worked for an electrician, i recommend it before doing anything. that way you will see if its what you want to do for certain.
if you have, then take classes. the best way to learn the work is in the field. to learn the technical aspects, use home study books along with classroom time.
considering the amount of time required to become proficient as an electrician you should be aware that you may not earn as much over the course of your career as compared to other lines of work. when i got my 4 year journeymans card the people working in the car wash next door were making as much as we were and it probably hasnt changed much since then.
