Hi, Jen,
I bought an iphone last year for the sole purpose of skyping back home from the Camino. I wound up being able to skype my elderly parents almost every day. It was great. I didn't walk the Frances, but I think my experience is what you are likely to find in all of Spain. There is wifi everywhere, even in the smallest towns, so if you have either a phone with Skype or an ipad or something like that, I think you will find wifi very easily. And I also found that bar owners were very helpful in finding me a quiet spot with good reception. On one occasion, the owner took me upstairs to her home over the bar, where the reception was stronger.
If you don't have an iphone, ipad, etc, you will have to rely on Internet cafes and what are called "locutorios" in Spain -- places with phones, computers, etc, with very reasonable rates. Usually available in cities or in towns with large immigrant poppulations. Libraries and "casas de cultura" and other social services type places usually have free computers for public use, but they usually don't allow you to carry on a conversation. If you have a smartphone, though, they will almost always have wifi too, so you can find a place in the hallway to skype.
Buen camino, Laurie