fruux - Free service that takes care of your contacts, calendars and more so you don't have to.
GO Contact Sync Mod - GO Contact Sync Mod is an open source tool to synchronize your Microsoft Outlook contacts with...
FullContact - Put the power of full contact information into your web or mobile apps.
Outlook CalDav Synchronizer - Free Outlook Plugin, which synchronizes events, tasks and contacts between Outlook and Google...
Google Contacts - Google Contacts is Google's contact management tool that is available in its free email service Gmail, as a standalone service, and as a part of Google's business-oriented suite of web apps Google Apps.
Outlook Google Calendar Sync - Offers calendar synchronisation between Outlook and Google, including attendees and reminders.