I'm blogging on this since I use Thunderbird as my email/calendar client on OpenSolaris (it's the default anyway).

It's easy to enable bi-directional integration of Google Calendar within Thunderbird Lightning, so here it is.

1. I'll save you abit of a chase, download the Google Calendar Provider is here: https://addons.mozilla.org/en-US/thunderbird/addon/4631

2. Now that you have d/l'd the extension, open from Thunderbird: Tools > Add-ons > Extensions > (bottom left corner Install), which will provide you with a window to select the location you downloaded to, select it and you're done installing, other than the restart. On to step 3., the configuration.

3. Now you can add your Google Calendar by going to Calendar > Add new calendar > (select the On the Network radio button) > (select the Google Calendar radio button) and enter the location, which will be the ical link of your google calendar. You will be prompted for your login information.

You should be good to go, go ahead and make a test calendar entry from Lighting and check your Google Calendar via a browser for the test entry.