I know these deals have been hit and miss in the past, but I had it confirmed with the SKY installation man today when he installed mine.
I phoned SKY last week and said I wanted an HD box. The inevitable costs were spouted at me, so I asked to cancel. Instantly they stated they could supply me a free, brand new 250gb SKY + HD box, free installation with no HD subscription.
I have had it installed today and the most common HD channels are free, inc BBC HD, ITV HD, Channel 4, 5 HD etc are all free.
The SKY installer stated to have it all for free is now pretty much the norm as long as you ask!
Thanks to 'kvn618' who rightfully states, as I forgot to mention, you can have 6 months half price instead if you'd prefer. Either way its a winner!