Installing shadow/md5 passwords after the fact?

["Ross Smith" <ross@uprizer.com>]

I recently installed 2.2r0 and said no to the shadow/MD5 questions during installation 'cause I was gonna install NIS.

Now I'd like to turn on shadow & MD5 passwords.  It seems that turning on MD5 passwords is as simple as 

# /etc/pam.d/login:
password   required   pam_unix.so nullok obscure min=4 max=8 md5

# /etc/pam.d/passwd
password   required   pam_unix.so nullok obscure min=4 max=8 md5

But I can't find any mention of turning on shadow passwords.

Any help would be greatly appreciated.

-Ross