A new vtiger CRM plugin, vgcal, has been contributed to vtiger forge recently to make it easy to interate with Google Calendar.
With vgcal, You can add/update vtiger calendar events on to your Google Calendar with a click of a button.
To know more about it, please view the document below:
http://forge.vtiger.com/frs/download.php/547/vgcal-v1.0.pdf
vgcal Download link:
http://forge.vtiger.com/frs/download.php/546/vgcal-1.0.zip
Project URL: http://forge.vtiger.com/projects/vgcal/
Kindly update us with your feedback on this forum post:
http://forums.vtiger.com/viewtopic.php?t=19810