The EyeToy captures great video at 640x480. According to this link there are Linux drivers for the EyeToy.
There's also some discussion at this page that references something called ARToolKit (Sourceforge project page) which can use the EyeToy.
If someone could compile up the necessary drivers/software to use the EyeToy via USB on the 6k, that would be pretty slick. The Zaurus + the EyeToy wouldn't be the smallest or best portable digital video camera available, but it's free if you've got the parts... Like I do