Microsoft outlook and Linux mail servers?

I was wondering if you ran a linux mail server, and had the end users connect to the mail server with outlook, would they be able to see the email ?
or
convince everyone to use like thunderbird ?

Yes, I know about exchange server…but don’t wanna spend a ton of money on 50 employees.

linux groupware, which one is the best?

i’m looking for a groupware software that i can implement in my office. there are about 50 people working there, i need email, calendaring, messaging, colaboration feature. more importantly i need the ones that are free. i’m running suse 10.0 goldmaster.
please give some explanation on:
1. why do you think your choice is the best compared to other
groupwares?
2. does it come with RPM modules or debian one?

PS: on e-mail client, we use either thunderbird or evolution

Thanks

How can I install programs on Linux?

I have the newest Ubuntu release.
I need to install: Thunderbird, a .rpm file and .so files. Are there any other types of installation? What are they and how to do them?
Thanks.

I’ve observed that file sizes of installers/setups of programs for Linux and UNIX are generally larger than their ports for Microsoft Windows. Examples of these include Mozilla Firefox, Thunderbird, Sunbird, JRE, OpenOffice.org, etc.

One example can be seen here:-

http://download.openoffice.org/680/

Why is this so? Does it have something to do with the architecture of Linux/UNIX? Do smaller file sizes of Windows counterparts imply a better API or better compilers?