Any UK contracts/sims will work here if you clear it with your network. If you want to keep a UK number live, I'd either reduce your contract to the min monthly, or make it pay as you go. Then get a local sim for your existing phone, which you can do at the airport.
You may have to get your phone unlocked, my blackberry had to be, but not saying all need to be. Plenty of places to have it unlocked here if it doesn't work.
Hope that helps!