http://en.wikipedia.org/wiki/Automated_airport_weather_station
check it out for the simple definition of these stations. Some notable differences are "surface observation" vs "weather observation". Run by the FAA, computer generated.
Would also be impressive if you were able to answer some addition questions when interpriting the METAR under REMARKS when knowing the difference between A01 A02 is which is without or with precipitation discriminator and generated METAR by the same systems. ATIS is usually human voice recorded in the slower airports but larger airports now have the computer generated voice that gives you, in addition to weather, the same important terminal information that is usually also covered in NOTAMS for that airport, as well as telling you which approach, departure, and RWY in use. It is in the AIM as well. but I didn't bother to look, since I've used these all over the country in the last few weeks especially. Clear as mud.