Keychain is a front end for ssh-agent which sets up one ssh-agent session per machine reboot. Useful for unattended backups, and so on, as the key passwords need only be provided once per reboot.
To fix SSH agent forwarding, set the $SSH_AUTH_SOCK value. I copied it from my first login into my screen session and it worked fine. :-)
Useful list of keyboard symbols. I used it when creating new shortcuts for quicktile.py.