My wife and i and another couple will be flying into Barcelona October 9, 2008 and flying out of Madrid October 20, 2008. The plan is to spend a few days in Barcelona and maybe do a day trip via train and then take a train to Madrid with the possibility of stopping for a day/night in Zaragoza along the way and then take at least one day trip by train from Madrid.
Will the Eurail Pass work for all trains? There seem to be many different kinds. Also, the passes seem to be sold through different sites, are all these sites legitimate? Anything i need to watch out for?
I have seen ST posts about flying economically within Spain, i haven't ruled this completely out but i am favoring rail because we have traveled by rail in France and Italy and have had enjoyable experiences, however we have always purchased tickets and have never used a pass so any insight into this would be appreciated.

I don't know much about the situation in Spain, but: Are you traveling in other countries in Europe, making the Eurailpass worthwhile? Otherwise, maybe you're asking about a Spain-only pass. In Italy, with a comparable itinerary, you would be better off getting point-to-point tickets. With what you say about experience with this in other countries, does it mean that you've compared the cost of point-to-point tickets in Spain and find the pass a better deal? Do you know if you'd still need to pay supplements for faster trains? That would be an important consideration.

We would be traveling within Spain only. The Eurail Spain pass for 5 days of travel is $ 272 for 2nd class. I think individual tickets would probably be less but i didn't know if the pass would be more convenient and flexible. I do not know if supplements apply or not. Also i read somewhere that a small additional charge is applicable for "reservations" but i haven't researched that yet.

We used Eurail throughout Belgium, France, Italy & Spain. We enjoyed the trains in Spain, however, on some legs we found the "small additional charge" to make a reservation quite "large"! Our day trip to Toledo was cheaper buying extra tickets than making a reservation on our Eurail Pass.

Zaragoza was quite an interesting spot to break the journey between Barcelona & Madrid - we enjoyed our day there.