Shortly after releasing a tool for synchronizing Google Calendar with Outlook yesterday, Google released another key in the synchronization puzzle: an API for accessing Google contacts.

The API will enable trusted 3rd party sites to access your Google contact information without asking you to provide your login information. So next time Facebook, Plaxo, or another service wants to import your Gmail, Google Calendar, or Google Talk contacts you might not have to give up your email password. Likewise, 3rd party software and web sites will be able to export contact lists to Google. And developers could write software that will keep your Google contacts synchronized with your desktop or mobile personal information manager.

In other words, if someone has some free time on their hands, they can write an application that will allow you to synchronize your Outlook and Google contacts. You know, like the application we were kind of hoping Google would release along with Google Calendar Sync yesterday.