Apparently Sony screwed up their press embargo thing, as things have been showing up here and there online, including their own web site.

Press release: http://www.livingroom.org.au/photolog/reviews/sony/sony_alpha_dslra100.php

Short summary:

The camera has a 10MP sensor (probably the same as the Nikon D200) that supports 3fps (versus Nikon's 5fps). They use a variant on Konica-Minolta's anti-shake via moving the sensor around, and have a new anti-dust feature as well. Sony has relabelled the old Konica-Minolta lenses as "Sony" lenses and added several new Zeiss-branded lenses. List here.

Sony's intro package has the camera plus an 18-70 zoom for $999. That competes favorably with the Canon Rebel XT + 17-85IS zoom ($1069 as a kit at B&H). Nikon doesn't have anything I'd call comparable. Nikon kits are either much cheaper (based on the D50), or much more expensive (based on the D200).

One might expect that the existing 6MP K-M bodies will be relabelled / repackaged as Sony bodies, giving Sony a complete product line in time for Christmas, with the A100 as the top of the line and the other cameras to compete at the $600 entry D-SLR kit level.

It's also quite reasonable to speculate that Canon will continue to be the top dog for a while, with Sony and Nikon duking it out for 2nd place, at least in the consumer space. Sony doesn't yet have the high-end lenses or body features to be a serious player for professional photojournalists, but they're definitely in the game now for the advanced amateurs. Pentax may get some mileage out of their partnership with Samsung, but we'll see. Olympus is screwed, as is the "4/3 system", which I imagine is unlikely to gain any serious adoption (even if the new Panasonic/Leica camera supports it).

One other prediction: these 10MP sensors are going to be all over the D-SLR market, maybe by Christmas. Pentax has already announced one. I'd expect Nikon to rev the D50/D70s line as well.