cooperation?

Greetings

We are planning to develop an interactive multimedia encyclopedia (animation, video, audio, data) for a global market.
We are in the stage of choosing the required technology for the application development (C++ is in our top choice).
The goal is to develop an mm-application that will work on most platforms (win, OS, Linux).

In what ways can we implement, or to be precise, in what ways can this new standard help us in achieving that goal?