My comments are predictably low-tech, but I think I have a pretty good system for staying in touch. First, in 2002 we bought a movistar phone for 25E that included 25E of phone time. I have used that phone every year since, buying a new card (which comes with a new number) as soon as I arrive in Spain. We use that phone for intra-Spain calls and emergencies, and my family knows it is on every night for a couple of hours. I know you asked about France, but I'm assuming you can find something equivalent there, a cheap phone with pre-paid time not a contract.
For calling home to the US, which I did every day or so, I used one of those calling cards Lynne mentioned. They are 6 or 7 E and available in every tabacalera or estanco (tobacco shop with a band the color of the Spanish flag on the store somewhere). Depending on the brand, you may get a lot of time. I have found that EuroCity is very good, for example. The problem with these cards is that many have hidden connection fees, etc, but a little bit of trial and error will help a lot, and there is usually a pretty good supply available in even the littlest tabacalera.
If you're using those cards, there are certain tricks that you can learn just by paying attention. The main one I remember is that those green and blue phones that sit on the bar and take coins usually give you a hugely better rate than the regular pay phones, as judged by the number of minutes that the recording tells you you have. But again, this is just in Spain.
Sorry, don't mean to get too much off-topic, but I think people could save a lot of expense and gear-hauling with a low tech alternative. Of course, you give up in convenience, but pay phones in Spain are not the dying breed they are in the US (unless things have changed since last May). Laurie
