Two-ways Sync between Thunderbird and Google Calendar

Background

I use Ubuntu 9.04 that comes with thunderbird 2.0.0.23 and lightning 0.9 in its repo. I have only one calendar in my Google account.

1. Open thunderbird
2. Click Calendar icon (left bottom)
3. Right click on Calendar dropdown menu and choose New Calendar … or go to Calendar > New Calendar …
4. Choose “On the Network” for your new calendar location
5. Select “CalDAV”
6. Fill location with “https://www.google.com/calendar/dav/username@gmail.com/events”
7. Hit “Next” and you will asked about your calendar name, color and your email address
8. Hit “Next” again and you’re done