View source for SSH Public Key Authentication

In a terminal on the local machine, type:
 ssh-keygen -t dsa
 cd ~/.ssh

You'll then need to copy it to the remote host, you can do this via scp (command below) or via some other secure method.
 scp id_dsa.pub user@remote_host:.ssh/id_dsa.pub.new

ssh (or otherwise gain access) to the remote host and do the following:

 cd ~/.ssh
Cat the public key from the client into the authorized_keys file
 cat id_dsa.pub.new >> authorized_keys

That's it.