mountd is deprecated, who knows if it will be dropped completely in near future (i.e in froyo release)?
vold2 is another option, but I don't remember if set/unset SYSFS_DEPRECATED is required for it.

As far /sdcard is always mounted and Android is not functional with back cover removed mountd or vold is not really needed at all. However, we need tell to Android card is always mounted and mount it from script at boot time.