I plan to travel from Barcelona to Toulouse in August 2013. What is the best way to go?
According to the timetables on the German Rail site, your fastest route is Barcelona Sants - Figueres Vilafant - Toulouse-Matabiau. Depart at 09:05 and arrive at 13:11 or depart at 16:14 and arrive at 20:11.
A slower but extremely scenic route is over the Pyrenees changing from Spanish to French rail at La Tour de Carol. It won't show up on bahn.de as the Spanish half is, despite the distance, officially part of the Barcelona local rail network.