As a non-windows OS user, I every now and then encounter problems with syncing up with ‘enterprise’ it infrastructures that require you to use either Outlook, or, well we have this very open HTTP based webmail… No longer, I’m using DavMail now for this, a POP/IMAP/SMTP/Caldav/Carddav/LDAP exchange gateway allowing users to use any mail/calendar client (e.g. Thunderbird with Lightning or Apple Mail/iCal) with an Exchange server, even from the internet or behind a firewall through Outlook Web Access.