vsftp vs shell logins

[techlist06 at msws.org (techlist)]

I need to be able to allow specific system accounts to ftp to a box.  As far 
as I can tell I have to give them a shell in /etc/passwd (i.e. /bin/bash) in 
order for their ftp login to work.  I do *not* however want them to be able 
to log into a shell or ssh session.  I cannot restrict by IP.  What's the 
best way to accomplish this?

Thanks,
Scott