The new ssl cert has been installed on the pop3 daemon on port 995. You can now configure your mail programs to login using ssl. In Outlook Express you'll find the option under the Advanced tab of your Account properties.
A couple of notes for others who may want to do the same with uw-imap. You need to decrypt your key if you used a password and if your CA is chained you'll need to cat it to the end of your ipop3d.pem file like:
openssl rsa -in mail.key -out mail.key.unencrypted
cat mail.key.unencrypted > ipop3d.pem
cat mail.cer >> ipop3d.pem
cat sf_issuing.crt >> ipop3d.pem
/etc/init.d/xinetd restart
Test your setup:
openssl s_client -connect mail.lewiscounty.com:995