Full time students and teachers can obtain an International Student (or Teacher) Identity Card. This costs £E100 (2011 price excluding any backsheesh or surcharge that the office may try to add on) and is obtained in Luxor at Jeddah Tours. I've marked this on the map. It is in a small road behind Luxor Temple. The card is valid from September of one year to December of the following year. It entitles the holder to big reductions on entry fees and rail travel in Egypt. See here for details.