Calendaring is an integral feature of the Nexus system. If you want to use calendaring in clients other than Microsoft Outlook, Entourage or Internet Explorer then you will need to perform further setup and configuration procedures. One method is to use Davmail and this document outlines how to use this program inconjunction with Mozilla Thunderbird, and its calendaring plugin Lightning, to access your Nexus account.
Davmail is an Exchange gateway allowing users to connect to Exchange via an alternate email/calendar client. It is available for Windows, Mac and Linux operating systems. This particular guide has been written using Ubuntu 9.04, Thunderbird 2.0.0.x and Lightning 0.9. It has also been tested on the beta version of Thunderbird 3 and Lightning 1.0pre.