Yesterday, we released our first alpha package of a MOST driver for Linux and Linux RT.
It currently supports the MOST PCI card OS8604 from SMSC/Oasis and can be compiled for Linux 2.6 or Linux RTDM (thus supporting RTAI and Xenomai). It provides a direct user space interface as well as an interface to the ALSA sound framework.
Support for transfer of asynchronous data is not available yet.
Please see the project home page http://most4linux.sourceforge.net/ for further details.