Barcelona = street art. Here are some links: this video about the current state of things, by BCN Mes, the best paper (subtitled in English).
Where to buy spray paint in barna.
A church with a graffitied dome (inside, that is).
This man gives walking tours of BCN street art.
I think this dude's work is great. I first spotted it on a churrería near my church.
And I was really happy to see so many space invaders in Paris. We need a few more of these guys over here.