There are some myths circulated about olive oil, such as, does olive oil lose its benefits when heated.
Heating olive oil will not change its health aspects, only the flavor. Excessively heating will evaporate the alcohols and esters which make up its delicate taste and fragrance. Ideally olive oil really shouldn't be used for intense heat frying such as deep frying, but for light sauteing where the temperature is lower than 180C, it's fine. It's best however to use a cheaper olive oil which doesn't have much flavor to begin with if you want to fry with it, and add a more flavorful olive oil after cooking or at the table to add taste and healthful anti-oxidants.