I noticed the lack of ssh-copy-id for osx and decided to develop the command line utility copymykey, which appends the specified key to the specified server. It has the default of .ssh/id_rsa.pub to .ssh/authorized_keys or allows you to specified the location manually. It is a great replacement for the missing ssh-copy-id. Once you copy it, it even tests the connection for you shortly aftwards.
Mac OS X 10.7
Mac OS X 10.8