There are quite a lot of sites on the web that can advise you about property buying. The only advice I can give you is related to places I know that would be nice to live - in other words, head south. My favourite part of Spain is Granada province.
As for websites, this should start you off;
http://mortgages-in-spain.com/cgi-bin/index.pl
http://www.escapetospain.co.uk/buying_costs.asp
Good luck