RoamTheWorldCellPhones.com

Cellphone GSM Frequencies: 900/1800

(This means you will need a GSM cellphone that will work on 900MHz or 1800Mhz to use it in Spain.)

Cellular carriers for Spain

France Telecom España SA (Orange)

Frequency: GSM 900/1800
Website: www.orange.es

Coverage Map (NONE)

Telefonica Moviles España S.A. (movistar)

Frequency: GSM 900/1800
Website: www.movistar.com

Coverage Map (NONE)

Vodafone Espana S.A.U.

Frequency: GSM 900/1800
Website: www.vodafone.es

Coverage Map (NONE)

If you've used either of these networks or roamed in Spain, please post about your experience and the cost. Feel free to ask questions.