I just switched over from Thunderbird to Evolution because of an issue with our IPSwitch mail at work. One thing that I had to search for was how to integrate my Google Calendar account with Evolution.
I found a tool called GCALDaemon. It runs as a service in the background and keeps Evolution calendars synced with Google Calendars.
The installation was pretty easy although I didn’t find a package in the repositories. The How To gives the instructions for installing. But, I didn’t find any tutorials for adding it as a service that automatically starts with the machine or with login.
Another How To describes the steps for configuring it for Evolution. It also helped to looked at the How To for Rainlender.
GCALDaemon looked like it had some other cool features like: Integration with GMail Notifier, Integration with SendMail, and Remote Controlling Your Computer with MailTerm.
Ubuntu Forums: Syncing Evolution to Google Calendar, and devices — How?