as far as I know it is not...
I was looking into this a while back and was unable to find a good practical way. it works with a .mac membership over the internet but i couldn't get it to sync over a local network.
if you just need to move the calender from one machine to the other you can go to file>export... this will give you a file that you can import to your other computer, but this is laborious. not the nice easy sync that you are looking for.
sorry I couldn't be of more help, let me know if you find a cool way to do it. i'd be interested.