A very interesting hack has come to light that lets any Canon DSLR capable of Live View record video. The camera itself is not modified in any way; rather, the dSLR is connected to a Windows computer via USB cable, and software is run on the computer.
The solution may seem clunky, and it's obvious that no professional filmmakers will use it for video; after all, if they want a portable high-end recorder, they can probably shell out for the 5D Mark II. Amateurs and students could end up using this to great effect, and it's clear from the samples below that (given proper mounts and less shaking) this has significant potential. Pair this up with a netbook and mic, and you've got an eminently capable portable video recording setup.
The video from a 450D above shows that even "low-end" DSLRs can manage the feat, and open up all sorts of interesting new video possibilities. News is still coming out, but one user reports that the video captured from his 40D was 1024x680 @ 25fps.