During the Technical Preview the features and functionality of the Office Web Apps will be limited. Currently you can create, view, and edit PowerPoint and Excel files and view Word documents in the browser. Additional functionality and features will be added in the upcoming months as we continue to gather feedback from people like you..
If you have not been invited to the Technical Preview, you will not be able to access the Office Web Apps yet. We are currently expanding our user base and will communicate when they are available for public use.