Rated 5 out of 5 stars
Just wanted to share a great free way I discovered to synchronize multiple Lightning calendars and tasks - install a Dropbox on your computer.
When creating a calendar (in Windows), simply point the network pointer to "file:\\\<<Path to Dropbox .ics file>> which it sees as a local file. Do the same on the other computers on which Dropbox is also installed. You can create as many calendars or task lists as you wish and updating across the network is almost instantaneous.
Syncing Tasks & Calendars Rated 5 out of 5 stars
I've just started syncing my Thunderbird Tasks and Calendars with memotoo.com and it works great! I'm using the Funambol sync add-on. You can only use one calendar but you can have multiple categories within a calendar. Tasks are attached to the one calendar.
Memotoo can sync with Google Calendar including tasks.