how do I make yum work?

[Michael Hennebry <hennebry web cs ndsu nodak edu>]

After yet another fresh install of FC3, I
tried to update with yum:
[hennebry 24-117-46-53 ~]$  su -
Password:
[root 24-117-46-53 ~]# yum update

You have enabled checking of packages via GPG keys. This is a good thing.
However, you do not have any GPG public keys installed. You need to
download
the keys for packages you wish to install and install them.
You can do that by running the command:
    rpm --import public.gpg.key
For more information contact your distribution or package provider.
[root 24-117-46-53 ~]# rpm --import public.gpg.key
error: public.gpg.key: import read failed.
[root 24-117-46-53 ~]#

Now what?
If the answer is RTFM, WITFM?
Googling yum FAQ didn't help.

-- 
Mike   hennebry web cs ndsu NoDak edu
"There are three kinds of people,
those who can count and those who can't."