Well, say you want to use key-based authentication to log in from machine A to machine B, you need to:
1) Run ssh-keygen on machine A, this will create id_dsa.pub or id_rsa.pub file under /home/[yourusername]/.ssh on machine A.
ssh-keygen will ask you to set a passphrase for the key, if you don't want one (which is likely the case), just hit enter.
2) Open authorized keys file on machine B (under /home/[yourusername]/.ssh directory) to your favourite text editor. If the file isn't there yet, just create it.
3) Display the contents of id_?sa.pub file by doing: "cat $HOME/.ssh/id_?sa.pub" on the terminal on machine A. Without the quotes, of course.
4) Copy-paste the contents of id_?sa.pub to the end of authorized_keys file on the text editor. Save and exit.
There are plenty of other ways of doing this, but I think this is the easiest.
Last edited by alienDog; 02-13-2011 at 08:06 PM.