ESE Key Daemon is a multimedia keyboard driver for Linux. With the 2.6 kernel series it can also handle remote controls, as they are presented as keyboards. No kernel patch is required. It is a userspace program that pools /dev/input/event? interfaces for incoming keyboard key presses. Package also includes Funkey daemon for 2.4.
Gentoo GNU/Linux have esekeyd in portage as app-misc/esekeyd.