AOL has begun open beta testing of AOL Sync, a feature that allows Outlook contact and calendar updates to be synchronized wirelessly with a user's address book and calendar both in his AOL account and on his mobile device.

Powered by Funambol's open source SyncML push/sync software, AOL sync should be instantly compatible with more than 17 different brands of handset, including the iPhone, 27 different types of BlackBerry, and the multitude of Windows Mobile devices.

To initiate AOL Sync, a user registers his phone number, mobile carrier and device type, configures syncing, and then download the sync client if necessary (not all phones need to install the client).

AOL expects the final product to be introduced in a few weeks, at which point beta testers will automatically transition to the latest version.