Hey folks,
I'm about to head to France and Spain for 2 weeks and need some advice for some SIMs.

Perhaps I should explain what I am after and then see if anyone has suggestions.

Mrs. Space and I will be traveling with my folks in France (Paris and Bordeaux) and then Spain (San Sebastian , Rioja and Barcelona). I'm going to be using a VoIP server and some trickery to allow users from the states to call a local number in Virginia and connect to whatever cell number(s) we end up with for free. I also have a number in Paris and one in Barcelona that will connect to voip server...at which point I can do a number of things. If its one of our two cell phones calling, it will give us a dialtone just like we were in Virginia. If its anyone else, they have the option to dial either cell phone.
I'll have 2 unlocked phones with me.

The goal is to give house/pet sitters, work people (both my dad and I have trouble being truly out of the office), etc access to us. When callers (from the states or Europe) call then they'll get an option to press 1 for Mrs. Space and I or press 2 for my folks. In other words we'd like to each have a phone on us. We will also have a few ways to call home should we need to. Furthermore, we'd like to be able to call each other since we are likely to split up some.

Heres the question: do I buy 2 french sim cards and 2 spain cards? That seems way too expensive for what we need. Since we'll be in France first, can we get some kind of French SIM card that will work in Spain as well? Remember, I've given our paris and barcelona numbers to restaurants, hotels, and other European contacts that needed a number, so its not like we'll need to give the cell numbers to anyone. Also, what about incoming calls for free? Using my VoIP server I can call in, it recognizes my number and gives a busy signal, then it hangs up and calls me back on that number...IE no outgoing mins used. Do European carriers typically allow free incoming calls?

I know thats a lot of techno-craziness but I need some help with the underlying questions. Do I get 4 cards (2 french and 2 spanish) do I get one for each country? Do I get 1 'euro' card that works in both countries? Do I get a lot of minutes or can I take advantage of my 'free incoming' trick?

I feel crosseyed just typing that.