HotMount is a quick and dirty program (UN*X only) to handle the mounting and unmounting of hotswap hard drives. It watches the system log (/var/log/messages or
/var/everything/current) for insert and remove messages, and reacts accordingly. It allows for very easy mounting and unmounting of hotswap disks. Want to access files? Put disk in, browse to directory. Done? Yank the disk.
More on the project page.