Mail/Webmail solution for multiple domains on a Debian server

[roger at airwave.co.za (Roger Day)]

Greetings all

Looking for some assistance on getting a server configured to run 
mail for a number of clients.  They need POP/IMAP (and webmail) 
access for multiple users on multiple domains.

Previously I have used a 'packaged' product where the 'supplier' of 
the 'packaged solution' would preconfigure the server with their 
image.  This has a number of benefits but also a number of draw backs 
and
have thus decided to look for an alternative.....

In the past my mail solution has used Exim as MTA which has an LDAP 
tree for authentication etc.  The interface (control panel) for this 
LDAP
tree is a little java app that is not perfect but does the job 
nicely. 
(we build a ssh tunnel to port 389)

http://www-unix.mcs.anl.gov/~gawor/ldap/

The webmail client of choice has been http://www.horde.org/imp/ and 
uses Spamassin/ClamAV to try and remove some of the junk....

I am looking for comments on how good (or bad?) this way of doing it 
and
if anyone doing this or done so using something similar.  How 
practical is
it to try and cobble these components together?  I will consider 
using any
combination of components so long as it does the job well.....

The other factor is that right now I have very limited time so would 
like
to look to engage some 'hands on' assistance as I do not have any 
spare
time to research and implement - in other words a 'paid' gig.  Please
contact me off list and we can discuss that further if you can assist 
me
and are available.

The server is loaded with Debian and is currently configured with 
Apache, MySQL and PHP for some simple web site hosting for some of 
the same clients that need mail.  fwiw I do not have physical access 
the
the server as it in in a hosted environment so everything has to be 
done
remotely.

All the best


Roger