Someone claimed that T-Mobile UK retentions said they would probably have it in July, but it's not on their website as "coming soon".
After T-Mobile discontinued the HD2 (which I was kinda iffy on software-wise: I do like WM6.5, but there's no future in it) I had all but decided to go with the Desire when I'm up for an upgrade in August. However, I have major misgivings about its weird PenTile display - it's faking WVGA and it seems to turn greys pink. The capacitive sensor it shares with the Nexus One also doesn't look so great.
The Galaxy S looks like it might be the better option, as long as it can be rooted and gets Froyo. (Would be nice if you could run HTC Sense on it too.) I can live without notification lights and camera flashes more than I can with a weird screen with pink issues.
Edit: The Galaxy S screen also seems to be PenTile? Gah. I suppose it has a better GPU.. can't we have a high-end Android phone here with a proper screen?