Lightning is the working project name for an extension to tightly integrate calendar functionality (scheduling, tasks, etc.) into Thunderbird. Lightning brings the Sunbird calendar to the popular email client, Mozilla Thunderbird. Since it's an extension, Lightning is tightly integrated with Thunderbird, allowing it to easily perform email-related calendaring tasks.
Lightning is an iCalendar compatible integrated calendar application for Thunderbird and its just the perfect choice for me and gives me great flexibility and usability on day to day activities. Now you can directly addIt can be downloaded from https://addons.mozilla.org/en-US/thunderbird/addon/2313
Provider for Google Calendar is a Thunderbird extension that allows bidirectional access to Google Calendar. This extension allows Lightning to read and write events to a Google Calendar. And now all my existing Google Calender data a displayed in the Lightning calender and the updated I make are synchronized bidirectionally. It can be downloaded from https://addons.mozilla.org/en-US/thunderbird/addon/4631