Physical Security
Google maintains a network of datacenters around the world, and works hard to ensure that they are secure from any sort of physical threat. Take a look at this quick video overview.
Maintaining redundancy for these each facilities is also important, making sure that if one server holding data goes down, another one can quickly step in and take over for reliable data access.
2-Step Verification
Google offers an extra layer of security for accounts by using something called 2-step verification. This uses another layer of protection by requiring more than just a password to log in. You'll be able to use a smartphone to verify who you are when logging in from a remote location, and all of your Google services will be protected by automated password locks. You can learn more about turning this on here.
Chrome Browser
Using Chrome as your primary browser brings a host of features to your secure Google Apps experience. From its ability to autoupdate you to the latest version as well as sandboxing that enables each browser tab to be a process, you get advanced security for Google Apps and your Computer. And version 12 of Chrome, which was just released, even comes with advanced Adobe Flash and downloading security as well.
Security Issue Reporting
Google makes it easy for users to report suspected security issues through a number of channels. Enterprise partners are always encouraged to make the proper support requests to Google Enterprise Support, and there is also a handy security issues page where you can report a possible problem on an array of services. This gives you direct contact information for that service's security team.
This is just a few of the ways that Google is committed to making your data secure, and we'll be bringing you more information about protecting yourself in the cloud very soon. For now, you can check out Google's Security website to learn even more.