[horde] Resources requirement

[John Masters]

I am looking to install Horde/Imp on a VPS (Xen based). The projected
usage is 50 - 100 users with possibly 30% online at the same time. I
have been testing Horde on a Debian Etch system running on a VPS with
512MB Swap and 256MB Memory. Fine for one user but what are the
realistic requirements for my projected use?

Thanks in advance for any comments.
-- 
Regards, John