Passwordless ssh?

["Christopher J. Morrone" <morrone@capsl.udel.edu>]

Can someone tell me how to enable passwordless ssh under potato?  (ssh
1.2.26)

This is for the purpose of backups.  I have public key of the machine
which is doing the connecting in the backup user's authorized keys file,
and the user that is doing the connecting is in the backup user's .shosts
file.  However, the machine always insists on asking for a password.

There are similarly configured machines around here already, so this
should work...am I missing some PAM settings or something?