Run ssh-keygen on your local machine, it will ask for a passphrase, and when you supply that it will generate a pair of files in your .ssh dir: .identity (which is private key) and
.identity.pub (which is public key)
You would want to add the contents of your local .identity.pub file to the remote server's ~/.ssh/authorized_keys file (in your remote account). This will allow you to login to remote machine without entering login password.
Best document, as always is the manual page of ssh.
Amit