phone card to use in Spain

[snookhams]

Ds son is off to spain with a group of swimmers from all over essex in a few weeks time on a training camp, I would like to get him a phone card so that he can call us a couple of times as he will not know any of the others before he travels and he is getting a little bit concerned. I have never bought a phone card in this country to us in Europe- can it be done and can anyone recommend one and where we would buy it from. Thanxs