There are many low cost air carriers that fly to Murcia and
Alicante that can be booked online here are links to some on them:
http://www.ryanair.com/site/EN/
http://www.flybe.com/
http://www.easyjet.com/
http://www.britishairways.com
http://www.bmibaby.com
http://www.thomsonfly.com
http://www.mytravellite.com
http://flightchecker.moneysavingexpert.com/
http://travel.kelkoo.co.uk/b/a/c_172201_flights.html
http://www.buyaflight.co.uk/index.asp