From what I see on Vodafone Spain's website, they have a prepaid 3G option. That is absolutely the way to go if you would like to do more than just the basics you're talking about. €139 gets you the PCMCIA 3G card and and 25MB data transfer. Alternatively, get a prepaid card from Amena or Vodafone there, use it in your GPRS device and data will run you €2/MB. If you're gonna transfer over 3MB of data, the prepaid SIM will come out cheaper as it comes with €12 credit (6MB).