i heard about opengroupware being like an open source version of exchange....so i do some research and i find out that suse also makes something of this sort called "suse openexchange", now all i want is a mail server with web access (like owa for exchange), something like exchange 2003, which features calender and scheduling blah blah, all the bells and whistles....what do you guys recommend?

The only one I've used is MoreGroupware:
http://moregroupware.sourceforge.net

and what did you think about it?

It is good but uses a lot of javascript so it ain't much good on older clients. There are 2 calenders, a great mail system and more. It is eay to install so it may be worth jsut stiking it on a box and see what you think. We had a look at the SuSE offering too but I think there was some licencing thing with that (don't quote me though)

It was primarily setup for use with our new mail server which is part of our new authentication system (to be in production soon). This was designed to replace a horrible Novell system with a more cost-effective and reliable system:
1) Users login to a samba domain
1.a) Samba authenticates using LDAP
1.b) When a user is authenticated an iptables rule is inserted to let that machine have net access
1.c) Users can surf the net and get their files
2) Qmail receives mail and puts mail in virtual user directories - information comes from LDAP
2.a) If a courier account exists on LDAP thenmail can be sent to that user - qmail creates the directories when the first message is received.
3) courier-imap is used for mail retreival
3.a) Courier authenticates using LDAP
3.b) Mozilla and netscape are used on the client PCs
3.c) SquirrelMail is available for webmail and calendaring for old machines
3.d) MoreGroupware can be used with newer clients - All of it's authentication is also done using LDAP.

excellent, can it run on windows, or it needs to be on a linux platform?

I haven't run it as such but apparently it will:
http://moregroupware.sourceforge.net...html#id2884026

(Not that I reccomend running it on anything but linux for reliability)

of course, linux for life

SuSE openexchange is what i run....its a little buggy but there are regular patches....pretty crappy interface with outlook as well
very easy set-up tho....very user friendly as most SuSE products are...doesnt like non-Intel CPUs....the java that comes with it crashes on nonIntel....there is a fix but im not sure where it is....check out their mailing list archives....has details in there....
overall i would say i have been happy with it....once i got rid of KDE and put fluxbox on it has been beautiful

well this is an amd based server...so i think im going to go with moregroupware or opengroupware

mine was an amd dual....there is a fix like i said but i used the problem as an exuse to buy a new cpu and mobo instead