It's true that Freeview HD transmissions are scheduled to begin around December of this year, with suitable hardware hitting the streets a little later, but the crucial point is that this service will only be available in certain parts of the country at launch. It won't be a nationwide service until 2012 at the very earliest (regardless of what you may read to the contrary in the national press). Yes, plans are afoot to help speed the process along, particularly for the London area, but they are not - as yet - anything more than plans.
So even you do hold fire now and wait until next year to buy an IDTV with a Freeview-HD capable TV receiver (DVB-T2) built-in, it doesn't automatically follow that you'll then be able to watch Freeview HD straight away. You may still have to wait until the broadcasting capability reaches your area.
If you want to know more, check out the Ultimate Guide to Television, on sale now. We've got the facts straight from the broadcasters themselves - we interviewed the General Manager of Freeview, the Managing Director of Freesat, the head of BBC HD, Ofcom's senior adviser on the digital switchover and many other senior figures in broadcasting.