The professional solution is Nikon Camera Control software for about $150 - if you really need tethering for studio shooting, that price is nothing. But there are also free apps like Sofortbild on Mac; DCamCapture on Windows.
The D3000 isn't yet supported by Nikon's tethering software development kit, but they should get around to it soon. Canon does bundle their official remote software with the camera, so admittedly the situation there is a bit simpler.
No: the D3000 doesn't have video or live view. I think both are compromises anyway on DSLRs because they can't use their main autofocus sensor in that mode; camcorders are better-designed for HD video.
No: as far as I know, Nikon firmware has not been hacked.
So if out-of-the-box tethering, live-view and hackability are important, you will be happier with the XS. If you'd like to concentrate on taking pictures, you may be happier with the D3000 (and here's a detailed review that may interest you.)