I received a suspicious email today. I have a free Google Apps account and have never been billed for anything except the domain name.

The email I received included an attachment that I did not open. could this be a part of the scam?

Hello from Google,

We're attaching a copy of your monthly invoice, detailing your Google Enterprise activity, for your records. There's no action required on your part as we'll continue to charge you automatically using the payment info we have on file.

Invoice number: 7....3
Name: Me
Billing ID: 7....7

To review or make changes to your billing details, please visit your account. Here's how:
Sign in to your Google Enterprise Control Panel.
Click on 'Billing'.
Click on the '$' icon on the right hand side of the screen.
If you have any questions, visit our Help Center.

See you online,
The Google Billing Team