What is it?
The Edimax BR-6104K/BR-6104KP is a router based on Infineon's ADM5120P SoC. The CPU has a MIPS32 core. These devices have 16MiB of RAM, 2MiB of flash memory, 2 USB ports (BR-6104KP), a WAN port, and 4 ethernet ports.
Other Similar Hardware
CompUSA Router
Sweex LB000021
Dynamode BR-6004
See Adm5120 at linux-mips.org for a list of more similar devices
See also Mikrotik RouterBoards, they are based on ADM5120P SoC and have working OpenWRT support.
Installing Firmware
Currently, the only way to install OpenWRT is to build kamikaze and transfer the resulting image to the router via serial port. Please consult here (Midge). Here is a good HOWTO on installing a serial port.