Google Flights has launched for Spain, showing a comprehensive network of flights into and out of Spain, and a price comparision tool.
http://www.google.com/flights/
However, rather annoyingly, none of the major “low costs” such as Ryanair, Easyjet, LAN or Binter Canarias (who?!) allow their flights to appear on it.
You can also see a map showing stop overs, etc. Quite fun for about 45 seconds.
For some reason – prices are quoted in US$.
So, actually, it’s pretty useless. Probably good for the long distance flights tho’.