1. run ssh-agent to start a shell for ssh-keygen
2.run ssh-keygen to generate the needed keys
3. copy the users public key to the authorized_keys file of the remote machine
(authorized_keys2 if using ssh protocol 2)
Thats it. Your user should be able to log into the remote machine without passwords. You can also run programs on the remote machine just by doing:
ssh machine.mynet.com programname
Key authentication is pretty safe as long as the actual keys are safe. No passwords flying around the net for one thing, nothing to sniff
If your reading a specific howto and getting lost, where is it and where are you getting lost?