Google Calendar Sync now supports the 64-bit version of Outlook 2010, in addition to exisiting Google 32-bit version, announced Google.
"To start syncing your calendar with the 64-bit version of Outlook 2010, download Google Calendar Sync version 0.9.4.1. When the Settings window appears, enter your email address and password, choose your sync option and frequency, and you'll be all set.
Note that if you are already using Google Calendar Sync, you will need to download and install this new version in order to be able to sync with 64-bit Outlook (we are in the process of auto-updating everyone but reinstalling will ensure it works for you)," google explains.
[Source: Gmail blog]