the light bulb cover needs to be removed first (they are notoriously tight) you may need a 'boa' to remove the cover (brilliant little tools/ get one in B&Q). then you simply take the bulb out and put a new one in, you can buy universal oven lamps from any supermarket or diy store (take the old one with you for comparison) . Don't forget turn the cooker off at the wall first, you don't want any electric shocks!!
lorraine 'the ovencleaners', January 2011