ceramic hobs are best cleaned with hob brite ive recommended it for 15 years+ (sainsburys tesco asda)
it is a cream but it is agressive enough to clean ceramic hobs (its designed for the job) you can also use a hob scraper as well for the tough stuff this is a scraper with a flexible blade available from your better cookware shops
http://www.homecareproducts.co.uk/hobbrite.htm
maddogmadox the cooker engineer, September 2007