You can download the Office 2010 version for the following location:
Also, when you install Office 2010, you will have 3 options as displayed the following screenshot:
That means you can install office 2010 without affecting previously installed versions of your office product.
During my upgrade process, it upgraded my outlook 2007 to 2010 and left all other office components intact. I am not sure it by design or I did something wrong during my installation. Anyway, I am using 2010 outlook now and I really happy with the product.