Yes. To access a website via ssh, use the connection information.
The SSH key fingerprints for ssh.phx.nearlyfreespeech.net are in this FAQ entry.
SFTP and scp are supported. Port forwarding is supported but is only permitted for establishing secure remote connections to your MySQL database.
Important: Our ssh environment is provided solely for maintaining your website and is not to be used for any other purpose. This specifically prohibits using it for proxying, port forwarding, or anything similar. Automated access to the ssh server is likewise prohibited, with an exception allowing connections once per day for the purpose of making offsite backups.