The command in unix that would be most usefull to you is 'mount' - use 'man mount' to get more information about it. I don't know the partitioning scheme that OS X uses to name disks, but you can open the disk utility to get an idea. I think, once you know the disk name, you can use:
mkdir /tmp/mount_point (or where ever you want it to appear)
mount /dev/disk0s6 /tmp/mount_point (use /dev/whatever as the disk designation... I'm guessing (and likely wrong) about your situation)
Hope that helps, or at least gives you somewhere to start.
