Just following up to let others know that everything worked great with the SIM card. I highly recommend it! Having Google Maps with you at all times makes things sooo much easier. A few notes:

1. You can't top up your card outside of Spain, so make sure it's precharged with enough to get through your whole trip if you're not visiting Spain.

2. If you are in Spain, keep your phone in airplane mode when you don't need it. You only get 10MB/day there and that's VERY easy to blow through.

3. While in Spain, you can top up your card at any of the RIA shops. They are tiny cellphone stores/Inet cafes that are fairly easy to find.

4. If you travel to Switzerland, put your phone in airplane mode. You must enabled data roaming for the cards to work throughout Europe, but Switzerland isn't part of their network, so it'll quickly eat through your remaining credits.

5. I never could get the thing to work as an actual phone, but it didn't matter for me since I was just after data anyways. You could always use Skype on it, if all else fails.