Google Docs Notifier is a free notifier for Google Docs that sits in system tray, and notifies you whenever some document in your Google docs is updated. It also notifies you whenever a new Google docs is shared with you. You can access the changed document directly by clicking on Google Docs Notifier in the system tray. This works in same manner as Gmail notifier, and Google Reader notifier.
Google Docs Notifier is quite easy to use. After downloading and installing it, you can provide your Google docs credentials to link Google Docs Notifier with your Google docs account. You can link it with only one Google docs account ay any time. After that, it stays in the system tray, and continuously monitors documents in Google docs. Whenever it detects changes in some document, or detects some new document shared with you, it shows an alert in taskbar.
It also shows a number in taskbar that shows how many unread documents you have.
Google Docs Notifier is a useful utility if you use Google docs heavily. Download Google Docs Notifier here.