The TurboTax End User License Agreement (EULA) for the Basic, Deluxe, Premier, and Home & Business CD/Download versions allows you to install TurboTax on all computers owned by you. You may use your TurboTax software to prepare tax returns for you and your immediate family.
Here is an article that explains it further: http://turbotax.intuit.com/support/go/GEN12968