Do you keep checking the coolant? if so do you need to top it up all the time and it keeps disappearing?? if so it could be either a leaking hose, air block in the coolant system meaning you havnt enough coolant in, leaking radiator or more than likely its the headgasket thats gone. take off the oil cap and look for white or coffee coloured gunge or deposit or top up your coolant and see if all the water comes out of the exhaust while the engines running leaving a wet patch on the rd. a garage may charge around £200-£300 to repair this problem. however driving while its over heating can damage the engine quite severely so try not to and carry a bottle of water round with you in the meantime.
Matt
July 2006