Sunbird is our standalone
calendar application.
It doesn't need another client application to run at the cost of a larger download and higher memory requirements.
Because of its standalone nature, Sunbird does not offer any kind of tight integration with an e-mail application, such as
Mozilla Thunderbird.
Lightning is a calendar extension for
Mozilla Thunderbird. It offers calendaring features directly in the Thunderbird User Interface. Further integration features, such as e-mail invites or address book integration are planned for future releases.
04/01/2008
Jarod Simmons