PDF-to-Speech has been updated to run in the background like a media player. The update is considered beta while some bugs are iron out. The bugs however are no show-stoppers and will be fixed in future updates.
We suggested to the Android market to allow for beta version of programs to be posted on the market, so that we can release updates faster, and use the help of our users to find and fix bugs.
The next update will be mainly the bug fixing.
The big bug in the list for the next update is to enable the program to handle bigger PDFs.
Thanks for embracing the app, and providing so much feedback.