Anybody know of BBS software for Unix or Multiuser BBS for MS-DOS?

[Brad Templeton]

We want to set up a BBS for IBM PC users with the particular purpose of
providing software support and updates on an IBM-PC product.  Multi-user
ability would be nice.  So does anybody know of:

a) a BBS package for unix (Xenix System III) that provides simple features
such as electronic mail, bulletins, individual accounts and downloading via
xmodem and kermit

b) a BBS for dos that supports multiple dialin

c) A program to integrate existing unix tools (mail, news, download) in
a secure way (chroot is probably not enough)

d) Whether an existing system like Compuserve is the best.

e) The best BBS software for an IBM-PC if there is no multi-user.
-- 
Brad Templeton, Looking Glass Software Ltd. - Waterloo, Ontario 519/884-7473