If your flavor of Unix doesn't come with ssh-copy-id - does only Debian have it? - , then create a file called ssh-copy-id in your $PATH with:
cat ~/.ssh/*.pub | ssh $1 'mkdir .ssh; chmod 700 .ssh; cat>>.ssh/authorized_keys'
You can then copy your public key to another machine by running ssh-copy-id remoteuser@remotehostname.
