Buy exchange and run Outlook Web Access.
thanks for that info, just want to ask one more ..how about that software icewarp or the freeware squirre mail..it's just the web mail interface still need exchange to keep this software running, am i right to say this? :(
You could setup a linux/freebsd server with POSTFIX/Sendmail/Qmail/exim & squirrelmail and run the whole setup with free software. I'm not sure if there is a viable option for windows.