if you don't have the file:
mac:~ traversfenton$ cd
mac:~ traversfenton$ ls -al .ssh/id_rsa.pub
-rw-r--r-- 1 traversfenton staff 422 17 Mar 2009 .ssh/id_rsa.pub
create it

copy it to the home dir of the ssh server with:
mac:~ traversfenton$ rsync -avP --stats .ssh/id_rsa.pub root@ovmserver:/root/.ssh/

now make sure the permissions and ownership are okay
mac:~ traversfenton$ ssh root@ovmserver
root@ovmserver's password:
[root@ovmserver ~]# cat .ssh/id_rsa.pub >> .ssh/authorized_keys
[root@ovmserver ~]# chmod 700 .ssh; chmod 600 .ssh/authorized_keys
[root@ovmserver .ssh]# chown root:root .ssh .ssh/authorized_keys
[root@ovmserver ~]# rm -f .ssh/id_rsa.pub