Oven lights are rated for high temperature 300 ºC and have a small screw (SES) fitting style - they are usually protected by a relatively thick and robust glass cover.
Circular covers unscrew anticlockwise and rectangular covers are mostly held in with sprung clips and will easily prise out with a largish flat-bladed screwdriver.
The major consideration when buying a new bulb is the Wattage - it will be printed on the glass bulb if you can read it.
Peccavi, January 2010
