Running Microsoft Exchange On a Linux Box - Can it be done?

["Angel Gabriel" <badmangabriel lycos co uk>]

I would like to know if anyone has managed to get M$ Exchange running on a
linux box. This is something that I would like to attempt.

The majority of my clients all use Outlook for thier Email/Calendaring/Life
organising etc, and it would be nice if I could offer them web access to
thier email, appointments, etc. The best solution so far, seems to be
microsoft exchange.

At least, they would be able to connect to us, no matter where they are, and
there is also a web interface, or use a client that they are comfortable
with, ie Outlook.

If there are any linux based alternitives... I would really, REALLY like to
hear about them.

Thanks in advance.