Some will already know how but this is for those that don't know you can get ITV HD on Sky HD.
You need to have the new EPG installed.
Go to Options/Add channels.
The settings are you need are:
Frequency(Ghz) 11.427 (this has to be entered manually with the number buttons)
Symbol Rate 27.5
Press yellow button to find channels.
ITV3 is shown as '10510'.
Select and press yellow again to store.
10510 will then be stored in the 'other channels' section.
Hope this helps someone, I only found out today and am now watching the chelsea game in HD.