You will have little trouble finding 'locutorios' (telephone booths inside booth-shops) or the typical street telephone booth. Form both of them you can make international calls. Telephone boxes will work not only with coins (warning, most don't return change) but with telephone cards ('tarjetas telefónicas') available at any official tobaco store, called 'estanco'. You will find cards with different prices.
'Telefónica' is the main telecommunications provider and a virtual monopoly (though the EU explicitly forbids monopolies). You will rarely find telephone boxes different from those from 'Telefonica'. To make an international call you have to dial '00' (double zero), then the country code and city/state code and the number to be reached. The country code to reach Spain from abroad is 34. If you require information on the telephone call on 11818 (you will be charged around 35 cents and can only recieve on piece of information, for example, the address of a shop). International information from telefónica costs 2,00 EUR on the number 11825. Spanish yellow pages call-center is reachable at 11888 with a cost of 25 Cent, per query. Rates of telephone calls should be available and visible inside telephone boxes.
Numbers starting by 900 are free. But numbers starting with 901, 902, 903, 904, 905, 906 are special services that can charge much more than the usual rates (call-centers, erotic services, ...).s
If your're thinking on a long stay you might be interested in getting a mobile phone. You can either make a contract (cheaper calls) or buy one just from a shop and use right aways through a chip-card (more expensive cost of calls). You can refill the credit on the chip-card in many cash machines, shops, stores and official 'estancos' (tobaco dealing shops). The main mobile companies are Amena, Vodafone and Telefónica Móviles.
THE POST 
Post services with its 6.000 offices reach all parts of the country. From this 'Correos offices (yellow is their corporate colour) you can send urgent packages, letters, get a P.O. Box to collect correspondence, send money internationally, send faxes, telegrams and connect to the internet.
Opening hours are from Monday to Saturday from 8.00AM to 15.00PM. On Sundays the central offices at big towns are also open. Airport post offices are open 24 hours every day of the week. There are post mailboxes on the streets where you can place your letters to be sent. Zip codes in spain have 5 numbers, the first two defining the province of destination .
Stamps can be bought at the post offices or at 'estancos' (official tobaco dealers). In some tourist destinations you can also buy them at some shops, though we recommend to buy them at official places.
Most international Express couriers exist in Spain, like UPS, DHL or FedEx but some local ones like SEUR can be more convenient at times
