There is an Apache POI library on code.google.com. However, the project does not seem to have too much activity. If other fellow developers are interested in the version we forked for Pdf-to-Speech, let us know and we will release the code under Apache 2.0 License.
Also, development on an Intent API to allow developer's apps to use Pdf-to-Speech is still an open proposition. However, we first need to see interest from fellow developers.
We are now focusing on providing features to increase user's access to their data, no matter where it is. And the addition of Google Docs-to-speech is still on the pipeline.