remote ssh command execution

Hi All, I was wondering, lets assume I have two computers, A & B, and from the desktop of computer A, I have a person click on a icon which runs a shell script which contains the following: ssh <someuser>@ sudo /etc/init.d/apache stop (or start) how can I make ssh NOT prompt the user for a password (but authentication via some other method, etc) and execute the command in question? I did read up on ssh-add and ssh-agent, but i'm not getting the hang of it? -Bill