Using ssh keys is very simple and really the only secure way to log into unix machines. Basically on any unix machine you run the command
ssh-keygen -t rsa
Which will then create two files in your .ssh directory id_rsa.pub and id_rsa. You can then put the contents of id_rsa.pub into the .ssh/authorized_keys file on any server, and you will no longer be prompted for a password when logging into the server. You can then copy your id_rsa file from to any machine you wish to login from, and you can login from that machine to any machine you put your key into the authorized_keys file, without prompting for a password.