[CentOS] CentOS friendly groupware

Just wondering what the consensus is around the list for a usable 
groupware product.  It doesn't have to be as "fancy" as the integration 
between Outlook and Exchange...just simple calendaring, ToDo lists, 
document sharing, contact manager, etc.

Has anyone tried opengroupware?  It seems to do what I need, but doesn't 
support Chinese (which would make life a lot easier for my folks in China).

Any suggestions would be greatly appreciated.

Cheers,