Hola peregrinos,
I want to share a great Apple app that I recently discovered. It's Postcards by Lonely Planet.
Download the app (it's free), take a photo from your iPhone or iPad (or use one of Lonely Planet's), add your message and postal address and send. A glossy postcard is printed and sent to your recipient. The card costs US$2.99 if originating from outside US to go anywhere in the world. Delivery to UK and US addresses within 3-7 days, longer elsewhere.
I tried it using one of my photos and the card that arrived looked great!
Last Camino, I sent a few postcards but finding cards, going to the Correos and buying sellos was a bit of a pain. And I don't know if this is the norm, but I had to have my card completed before the staff at the post office would sell me the stamps. Hard for someone like me who isn't necessarily inspired to write upon command.
Disclaimer: I don't work for Lonely Planet nor Apple.
PS I just discovered that there are other postcard apps too, not just the Lonely Planet one. Many seem to be more like greeting cards than travel postcards. But whatever tickles your fancy.