Cast your minds back to the end of September 2009 and the big day for the country dubbed "Retune". Yes, that was fun, wasn't it? Stepping round the risk of asking if everyone managed to get their channels back and their equipment working again, it might be time to remind us all why we went through it in the first place. Well, one of the big reasons was to make room for Freeview HD. So, what the hell is Freeview HD then?

Well, on the outside, it's the same old Freeview service that we already have, but what it also means is that Joe, Jane and little Jonny public will now be able to receive high definition TV channels for absolutely nothing. Yes. Free. Like the birds.

As it happens, the Freeview HD transmitters have already been switched on in certain areas of the country which means that both BBC HD and ITV HD are floating about our heads as we speak just waiting to get caught and put on a screen near you. Strictly speaking, it's not everywhere in the UK at the moment. Around 50% of the country should have it in time for the World Cup this summer - convenient as it'll be televised in HD on those two channels - but by the end of 2012 all but 1.5% of the nation will have access to it. If you want to see when it's coming to your house, then put your post code in the Freeview HD checker and have a look.

Channel 4 HD and Five HD are set to follow the other two services shortly and there might just be enough room to squeeze one more HD channel down the Freeview pipe some time in the future. Do be warned, though, that that's as many as you'll get - at least until there's a massive overhaul to the service and more bandwidth is bought up in the future.

To get Freeview HD, you'll either need to buy a new telly with a Freeview HD receiver built-in or a Freeview HD set top box to plug into your current screen. Bear in mind that you'll need an HD TV to appreciate the difference or it'll just look like the same old channels you had before. If you're not quite sure what HD is, then, well, that's one we'll have to troubleshoot another time. Suffice to say, if you can receive them, HD channels will offer more detailed, clearer pictures with better sound quality as well.

Worth getting in on the act if you can. After all, it is now free.