This is where things go on a Linux machine:

/

Called the filesystem root, this is where everything else on a Unix system resides on - either directly, or indirectly via one (or several cascaded) mount points.

/boot

Stores the kernel. Usuallly a seperate Partition at the beginning of the hard drive

/bin

System binary files (Programs) for use by all users

/dev

Device files. Represent all devices connected to your computer

/etc

Contains configuration files for programs

/home

Each user has a folder in here to store all their personal files. Commonly refered to as ''.

/lib

Contains libraries needed to run the programs in /bin and /sbin

/mnt

Provides a place to 'mount' temporary filesystems (eg CDROM, floppy disk)

/opt

Location for add on software. Usually StaticallyLinked? programs provided in binary form. Some people install TarBalls? in here too, expecially beta software.

/proc

A "live window" in to kernel parameters.

/root

home directory of the root SuperUser

/sbin

Exectuable files to be used only by the root SuperUser

/usr

For files that can be shared across a whole site among multiple users

/usr/local

Files that are installed from TarBalls? usually install to here. Contains a full directory structure (bin/, etc/)

/var

For variable data files

More information can be found at the filesystem hierarchy standard