GALsync version 4 provides an important and heavily requested new feature: synchronization of free/busy information.
Aditionally it has a new Look & Feel following Exchange 2010 and Outlook 2010. Unless we spent a lot of time in developing this feature, this version is a no chargeable upgrade.
see upgrade instructions here . . .
Download the latest version from our website http://www.netsec.de/index.php?id=download-2009&L=4
Extended information and tips
See GALsync blog at http://www.tools4Exchange.com/galsync
Upgrade Instructions for Existing Users
For upgrading from GALsync versions 2.x or GALsync 3.x to GALsync 4.x we recommend to backup your GALsync program folder.
Keep your settings written to paper before uninstalling your current version using the Add/Remove Programs applet in Windows Control Panel.
After installing the new version you have to re-configure all previous profiles. There is no task to migrate them directly, because version 4 uses new data structures.
You may re-use the current service account and its mailbox (if used).
Downgrading Back
Should you choose to downgrade back to your previous version of GALsync
the changes you make in your new installation will not be reflected in the previous, older version. For downgrading restore the backup of the GALsync program folder and run your previous installation file.
Licensing
This is a no chargeable upgrade. But you will require a new license file.
If you run version 4 without a license you will not be able to export more than 100 objects!
If you have any question or queries you can contact GALsync Technical Support on +49 2421 998 78 20. Alternatively, you can email them at support@netsec.de.

Just what I've been looking for and apparantly, much more too.