An integrated headset has the bearings race built into a wider section at the top and bottom of the head tube.
A non-integrated headset is press-fit into the head tube and has it's own bearing race that sits above and below (top and bottom) of the head tube.
An integrated headset has the bearings race built into a wider section at the top and bottom of the head tube.
A non-integrated headset is press-fit into the head tube and has it's own bearing race that sits above and below (top and bottom) of the head tube.
Here's an explanation of integrated versus internal (another type):
http://www.hiddennation.co.uk/Internal%20Headsets%20explained.htm
This is a normal aheadset, where the bearings are outside (above and below the frame head tube):
An integrated setup would have the bearings "inside" the frame, see how this headtube is wider?