I own a Plextor px-tv402u (a USB2 analog video capture device with hardware MPEG1,2,4 encoding - wis-go7007 chip) and have been successful in building the drivers for this device and capturing video. I run Debian lenny (Linux kernel 2.6.30-1-kirkwood) on my SheevaPlug on a 4GB SDHC card. I capture video on to a Western Digital Passport 320GB hard drive (mount /dev/sda1 /mnt). The hard drive and the Plextor px-tv402u are connected to a powered USB2 hub. The Plextor gets its analog signal from a digital tv converter box for over-the-air broadcast recording.
These are the build and install instructions:
aptitude install build-essential linux-headers-2.6.30-1-kirkwood libncurses5-dev fxload oss-compat
tar zxvf wis-go7007-linux-098-5.tgz
I can capture video using the gorecord app that comes with the drivers. I've had good results capturing a tv show with:
gorecord -input composite -mode ntsc -bitrate 1500 -width 720 -height 480 -duration 1860 -format mpeg2-dvd /mnt/capture.avi
I playback the video on my Western Digital WD TV. I just umount /mnt, unplug the hard drive from the USB hub, plug the hard drive into the WD TV, and watch the video on my tv. Very easy.
Now I just have to write a CGI program to write cron files to schedule recording. Then I will be able to setup the recording times using a web browser.