Microsoft Senior VPs Steve Sinofsky and Jon DeVaan (the former in charge of Windows and Windows Live and the latter in charge of Windows Core Operating Systems) have started a new joint blog called Engineering Windows 7 to talk about, well, Windows 7, the next version of Windows beyond Vista. So that would be Lost Horizon then (bada boom bada bing 
).
They're going to be regularly blogging about the new things in Windows 7 all the way up to PDC (Professional Developers Conference)in October -- where already there's a large number of sessions booked to talk about Windows 7 -- and WinHEC (Windows Hardware Engineering Conference) the week after. It seems that, after a virtual desert from the past couple of years, we're going to be deluged with information until we're drowning in the stuff.
The blog is bound to be interesting. My recommendation then is to subscribe to the RSS feed so you're kept up to date with what they say. (Well, as soon as it's ready; must be a Windows Live thing.)
(Er, Ray? I know that we're a Platinum Sponsor of PDC this year and that we have a large booth 'n' all and it's likely to be a madhouse in the Exhibitor's Hall, but could I have lots of time off to go to these sessions? Ray? Don't walk away laughing hysterically, I'm asking a serious question. No, don't switch the light off...)