I'm just wondering what is the difference between the two. Does a broadcast monitor need calibrating like a normal monitor?

A broadcast monitor can show you the Rec.709 workspace, which is a requirement for color correction and grading if your target is DVD, blu-ray, or broadcast HDTV. Nearly all computer monitors lack this workspace which is necessary for serious video work.

And yes, broadcast monitors need to be calibrated periodically.

what are they calibrated with?