Great news for Google users that have mobile phones: Google has released the API to contacts, meaning that developers can now create synchronization software for the address book. It is a big step ahead. Currently, it is possible to sync your google calendar to your mobile (using Google Sync) and have your gmail on your mobile in various ways (default supported by blackberry :P), addition of your contacts will make this a complete PIM se that travels with you whereever you go.

According to the Contacts API site, the new API allows application developers to enable their users to:

• Synchronize Google contacts with contacts on a mobile device
• Maintain relationships between people in social applications
• Give users the ability to communicate directly with their friends from external applications using phone, email, and IM

The Google Contacts API is here.