I do some international traveling with my work, so congrats that you are thinking about this, this far in adavance, although it has been a couple of years since I have been to Spain. The first thing I would suggest is to continue looking and connecting with someone who actually lives in Seville and who is techno savy. My hunch is that you are going to find that the system is probably a little bit different than you are used to at TT. Unless you are going to be in a strict university setting, I do not think you will find as many WI-FI locales as you might be thinking. Again, it is something important to check out.
I think that you need to decide what you need the machine for. If it is just to stay connected and keep in touch with the fam and friends back in the USA, then all the internet cafes will be just fine and you don't need any device. If you are going to use it in your studies, in your travels and on weekends, by all means take a PPC with a couple of good SD/CF cards. Two years ago, a buddy and I walked thru the Lake District for 10 days, about 110 miles. Everything we needed we had on my Ipaq and I used it for all the notes and reflections. We were really trying to travel light, but the Ipaq was essential. It was perfect and we did not need anything more than that.
Bon chance et bon voyage!!