I recently started playing with a "free" (for one year) trial of Amazon EC2.
One of the things it had me do is create a new RSA priv/pub key-pair for use
with SSH on the new server instance. Previously, I hadn't really messed with
managing multiple identities on SSH (I just added the id_rsa.pub file from
each of my machines to the authorized_keys files of my couple of toy
servers). But no more.

So anyway, knowing vaguely what ssh-agent was, I played with it and
currently I've added "ssh-add <identityfile> &>/dev/null" lines to
~/.profile, which works. But is there a more correct/better way to do this?
Is ssh-agent practically any better than adding an Identity option to a
corresponding server in ~/.ssh/config for my purposes?