Muahahahaha! I've seen the World Cup and Wimbledon in high definition too
And best of all... it's all FREE. None of this £300 (or whatever it is) Sky HD box to pay for.
There is limited content - so far it's been live sports, a few films/documentaries on BBC HD1, World Cup on ITV HD, random episodes of Lost/Desperate Housewives and the odd film on Channel 4. Five only started their HD test broadcasts last week - they were showing stuff like CSI.
The quality of the broadcasts really varies... the footie was kinda 'meh', rather grainy looking and no digital surround sound. Wimbledon was better with surround sound so you felt like you were actually on court, but the picture quality was still a little off. The Planet Earth series though really is something else. It's absolutely awesome in HD.
I signed up for this trial a few months ago. The trial started in June and I think it goes on to the end of the year. I got a free HD receiver box which I get to keep at the end and I just have to answer a few online questionnaires and take part in occasional telephone surveys. I haven't had a chance to watch that much of it so far, but I'm enjoying the HD content a lot more than SD TV.