Yes, you can.
Q1. How many times can the software be installed?
A1: A single product key for Microsoft Office for Mac can be used for the installation of Microsoft Office on one desktop computer for work purposes and one laptop for travel purposes, as long as both computers will not be using the software
at the same time. If either computer is replaced, the software can be removed from that computer and installed on the replacement computer (by using the same product key).
If the software has to be removed and reinstalled on a computer, the same product key can be used for the installation.
Quote from Office 2008 for Mac licensing frequently asked questions
For more questions about Office for Mac, we'd recommend you to visit the forums in Microsoft Community:
http://answers.microsoft.com/en-us/mac
Max Meng
TechNet Community Support
