A friend of mine rents out his house in Estepona, on the Costa del Sol and is offering 10% discount to mumsnetters. Just put in the email where you saw the link.
We've stayed a few times and it is great. Their roof terrace is amazing for lounging on. There isn't a pool but the beach is two mins away.
www.esteponatownhouse.com
I might get a discount if anyone books so fingers crossed!
PS I hope it's Ok to post this, I couldn't see a holiday rentals section.