HI,
The main reason a lot of sports coverage is still in 4:3 and not Widescreen, is actually fairly simple. It's down to the countries in which the sport is being transmitted from, and by which TV company.
Althought the US, Britain, some parts of Europe and the Far East have embraced Widescreen technology, many other countries haven't, or can't, due to political, technological or financial reasons. With some countries TV networks not having the ability to transmit widescreen material, they have to use 4:3.
Now, when it comes to sport, unless the channel you are watching the sport's coverage on, has their own Outside Broadcasting Unit (or OBU's), to transmit the material in Widescreen back to the UK in, then that channel, e.g. Sky Sports 3, or BBC1, have to rely on getting the coverage from another TV station.
If that TV station's coverage, (which will frequently be by the main national TV broadcaster in the sport's coverage's location), isn't in Widescreen, then there's nothing other broadcasters can do, to make it 16:9 compatible, unless they crop the original 4:3 footage.
Some broadcasters have done this: slapping black bars across the top and bottom of 4:3 material, to make it compatible for their Tv channel, but a lot of viewers (understandably) don't like it, and don't want it that way, because that's not how the original picture should be viewed. Hence, the compromise, where the broadcast is in 4:3.
Very few TV stations can afford to send their own, channel-specific OBU's out, to cover sport around the world. Sky and the BBC are about the only two exceptions. Even ITv can only cover certain UK-based football stadia with their own OBU's, but more often than not, they pay a fee to a local TV broadcaster to get their material, to transmit back to the main ITV channel, and this is often in 4:3 (as happened plenty of times with the recent World Cup coverage).
With Sky, they are happy to let other broadcasters pay them, for their footage, but at a high-price! But then, Sky are lucky to have enough to have both the financial, technological and physical support to be able to do this. And this is why, no matter where the sports (or news) coverage takes place, SKy can often get their own team of broadcasters' out to the location. The BBC can do this in some parts of the world, but ITV can't, and many other foreign TV broadcasters can't either.
Apologies for the length of explanation, but I hope it's been useful.
Pooch