Vendors Website: http://www.yuan.com.tw/en/products/vdo_mpc622.html
Support Status: Supported by Myth: Uses IVTV driver
A mini-pci form-factor card with support for hardware based mpeg2 encoding. Uses a Conexant cx23416 chip, the same as the popular HAUPPAUGE PVR-150. Pretty much a PVR-150 in mini-pci form-factor.
The driver for the Yuan MPC622 is the excellent IVTV driver, which has an excellent Wiki. They have all the links you need to download the drivers and firmware and an excellent HOWTO for installing everything for various distributions.
If you see an "Unreasonably low latency" message from ivtv in your logs you should probably read the page on PCI Latency
I'd suggest following the many guides for PVR-150 or PVR-500 cards. Adding this card to my system which uses, and was configured for, a PVR-500 resulted in it just working. Straight away. Card is very similar to a PVR-150, which the PVR-500 pretty much appears as two of.
Best info most likely found on the IVTV driver forum on Sourceforge. See also the wiki at: http://ivtv.writeme.ch/tiki-index.php
Only european supplier I could find was Picco Computers  Despite the page for the MPC622 saying they'd only sell it bundled with a motherboard they had no problem selling me one on it's own once I explained I really did have a mini-pci motherboard. I'd guess they just don't want people buying mini-pci when they only have pci slots!