OpenSSH
An open source SSH client and server. http://www.openssh.com
Regular Links:
SSH Communications Security
Extensive information about the SSH protocol. Has a variety of SSH products for sale, including clients, servers, and VPN software.
http://www.ssh.fi/
SSH Master FTP Site
Binaries for SSH1 and SSH2 clients and servers for Windows and Unix.
ftp://ftp.ssh.com/pub/ssh
SSH Patch Repository
NCSA's collection of patches for SSH.
http://www.ncsa.uiuc.edu/UserInfo/Resources/Software/SSH/patch_repository/SSH_patches.html