As mentioned elsewhere, sky intend to do HD early next year, my bet is we will see Prime, and Movie channel and a Sports Channel go HD. As is the experience in UK they will run native HD material when available and upconvert the rest of the time, the exception to this is a movie channel where for sometime now movies are transfered from film to video as 1080sF24/25 and from their sub masters in 576i50 and 480i60 are made for DVD and broadcast release. So 1080 masters exist of most recent and current film/movie material.
In this vein, I suspect (pure heresay) that Sky will push The Rugby Channel into HD first, as this is their 'premium channel' where users are already paying extra. All i hope more is that Sky will sort out the rest of their sports channels to broadcast in 16:9. Last year I did get a reply from them pretty much saying all channels except the RC aren't capable of broadcasting 16:9 signals at the moment, hence no cricket etc (from Channel 9) in 16:9.
I understand the rugby world cup host broadcaster will broadcast games in HD, but I doubt TV3 will get sorted in time to carry these games.