I'm going to be in Spain in July and would like to spend a week or two at a Spanish immersion school. Right now I'm considering the Pylmon School in Barcelona, which has a nice looking website, and I think Barcelona will be a fun place to spend a couple of weeks studying Spanish. Plus, it's fairly far north and on the beach, so it might be a little less sweltering than other parts of Spain in the summer. If any of you have had good experiences studying Spanish in Spain, though, I'd love to hear about them.

I've been to a couple of Spanish schools myself in Mexico, and the one I would most recommend is Instituto Miguel de Cervantes in Guanajuato. The teachers were fantastic, and Guanajuato is a wonderful place to hang out.

centro Humbolt and BCN are good schools too;for what i hear about them. I already know spanish,being Spanish.
but also note the official language in Barcelona is catalan,with what is know in english as spanish really is castilian.

Although the fact that barcelona speaks catalan shoudlnt affect your school too much, it still wont be 100% immersion as you will hear plenty of catalan on the streets and in writing. If i were you I would go somewhere more genuinely Spanish. There are other vibrant cities where it could be fun - like Mardid or Valencia (although Valencia has Valenciano also, it is only really spoken in the surrounding villages)