In the Linode Manager:
1. Click on your linode.
2. Click the Remote Access tab.
3. Scroll down to Console Access.
4. Enter a password in Lish via SSH Password if you don't already have one and click Change Password.
5. Copy the line to the right of Lish via SSH (looks something like this: ssh
linode123456@newark123.linode.com) into your terminal and press Enter.
6. Enter the password you just set when it prompts you.
From there on you can login using your regular user and password and change his key in ~/.ssh/authorized_keys to regain ssh access using youruser@yourlinode.