Oh dear this happened to me on Saturday,spilt a smirnoff ice all over my Nokia N80. The screen stopped working, I tried to dry it out on the radiator in a towell and although it is now all dried out the screen flickers and there is no backlight!
My advice would be to dry it out fully, then contact your contract provider and say your phone has stopped working and they will send you a replacement. Aslong as it is fully dried out before you send it back they should just think it is a faulty handset. Im going to send mine back to the catalogue hehe!