Microwave oven.........need help!!!!!!?

iam trying to learn a lil' bit of cooking these days and have come across quite a few recipes tat say 'pre heat the oven to so and so temp' but as there are no temperature settings in a microwave........my ques is hw to proceed?????? is microwave not a bogus device if it does not hav temp settings? wat does a microwave have that a simple oven does not??/