Vodafone was first with support of the phones, announcing at the event that they would sell both the Desire HD and Desire Z from mid-October, in Europe. While they haven't announced tariffs, it's expected to be the usual free up-front phone, on monthly plans starting at around £30 (in the UK at least).
TechRadar has reported that they've heard the Desire HD will be available on all of the UK networks except for O2, though that could change. T-Mobile has confirmed that they'll be selling the Desire HD from £40 a month—pricey, but then knowing from experience T-Mobile is generally pretty good at bargaining with.
Despite initial thoughts that these phones would be non-US launches, we heard from HTC US, who confirmed the Desire HD will be "shipping in North America later this year." No word on the Desire Z, but then it's far too similar to the G2 to warrant a launch there.
Back to the UK, and both phones will of course be sold through The Carphone Warehouse and Phones4U, plus Amazon, Play.com and various other online retailers. Amazon UK has confirmed it will cost £499 from October 18th, whereas Play.com has undercut them by £30, offering it for £470—with an earlier release date too, of October 11th.
The Desire Z is listed on Play.com for £430, with the same release date expected, and unfortunately Amazon hasn't improved its pricing for their offering of the Desire Z, which will cost £499 from the 18th.
We've waiting to hear back from all the UK networks about pricing, but if anyone spots any more deals, do get in touch.