Both 'HD' and 'HD ready' are used to describe TV sets which can display high definition pictures (so there's no real difference between the terms) but, confusingly, neither term indicates that the set is capable of actually receiving BROADCAST HD signals. All that those terms (on their own) tell you is that the set can display pictures in HD from an EXTERNAL source (such as a Blu-ray disk player, Sky HD box, Freeview HD box or a Freesat HD box).
Assuming that you're seeking to receive HD pictures via Freeview, what you really need to know is the difference between this logo (on the box of an 'HD', or 'HD ready', set):
http://www.ksat.co.uk...ges/freeview-logo.gif
and this one:
http://mos.futurenet..../FVHD_logo-420-90.jpg
The former logo simply means that the TV set can receive Freeview signals. It does NOT (even when on an 'HD', or 'HD ready', set) mean that it will get the Freeview HD channels. (i.e. the set just has an 'ordinary' digital tuner inside it, not the special one which you need for HD). The latter logo is what you're looking for if you want to get Freeview channels in HD.
Chris.