[mehulved]

There should be some option to show mounted disks on desktop, I am not on GNOME right now so I can't search for it. But, just check some settings you will find it.
It's better to mount such partitions and optical media under /mnt or /media cos HAL will detect the mounted media and will show it in Places menu. It's just a matter of making a directory under /media and editing your fstab file. It can be done through System =>Administration => Disks too.