Well, Outlook connector can't sync to OSS. (tryed)
The simplest way is to download NE edition, fill out the Deploy info to get the xml registration file on your mail and you can test it for 60 days unlimited.
Then you can also download Outlook Connector from admin console.
(you can also install software only to get Out. Conn. like 'install.sh -s' I think, then go to Zimbras tomcat/jetty folders and search folders for *.msi

)
Some page I found to download... ZCS_Connector_for_Outlook_Install_Process outlook-2007-beta-overview