Those who have a paid version of Microsoft Office Web Apps will be able to access them everywhere according to Directions on Microsoft analysts.
“The single primary user of the licensed device may access and use the software remotely from any device,” according to the Microsoft Product Use Rights (PUR) January 2010 document.
Also, one non-primary user may access and use the software from the licensed device.
The analysts’ discovery means that users can use Office Web Apps without having to purchase more licenses.
Source: Ars Technica