I don't know if this is a help to you, but you can do it with Google calendar by setting it up as an Exchange account. There are instructions somewhere on the Google site for doing this.
I setup a Google account, and installed their Google/Outlook sync application on my laptop. Any events I enter in Outlook go to Google and then to my phone, and any events I add in the phone will appear in Outlook.
If my wife does the same with her Outlook and phone and points them to the same Google account, then any event we enter will appear in all 4 places.
Ian