I am currently travelling through Spain and am spending around a month here. I too have been booking trains and accomodation on the hoof over the internet.

I have been using expedia.co.uk (or expedia.com if you want pricing in US Dollars instead of pounds) for a number of years not had any problems with my credit card. They have also been a useful way for me to book things at the last minute and sometimes they have a special deal on for last minute bookings.

Mark Sukhija, in Zaragoza