First of all synchronization is different from publishing.

• To synchronize means that no matter with which client (iCal o Google Calendar) changes are made on the calendar it is possible to see and edit the changes with another client, it’s bidirectional
• To publish means that changes can be made by one client only. The other client can only view the changes made, no editing is possible

Thus the scenario is: I have one or more calendars on iCal that I want to also see on Google Calendar without updating by hand or importing the calendar file each update I make to the events What do you need: iCal, Google Calendar account, icalx.com account. Let’s proceed by steps. 

• Create an account on icalx.com
• Access you account page and note the url at the bottom, something like http://icalx.com/public/youraccount/
• Open iCal, select the calendar you want to publish on you Google Calendar, right click and choose publish

• Select a Private Server form the Publish on drop down menu
• Fill in Base URL with the url you took note of before
• Fill in Login and Password with your icalx.com account name and password
• Click Publish 

• Logon icalx.com, you should see in the list of your calendar the calendar you have just added
• Move your mouse the the .ics link referring to your calendar and note the url 

• Logon your Google Calendar account
• Go to settings
• Press the Add Calendar Button

• On the new page select the Add by url tab 
• Paste in the address of you calendar that you should have noted a few steps ago
• You’re done!

 Whenever you’ll make changes with iCal to the published calendar they will reflect on Google Calendar too!