Regular size (
mini sim, not credit card size and not the even smaller micro). And xournal does have zoom, pan, and even note export as pdf, but don't hold your breath for a port.
Right now, the PocketBook does have nearly all libraries required to run Xournal, but the most crucial one - Gtk+ - is a hasty port, not suitable for annotations (it appears not to support calibration or strokes), and the sources for that have not been published. I have tried building Gtk+DirectFB programs to test it, and it doesn't seem trivial.
Perhaps I should have a closer look at how the DR800 solves it, normally Xournal expects an X server and uses XInput for better digitizer support.
Edit: Looks like the DR800 version does use X (it links to libgtk-x11-2.0.so.0). It might actually turn out to be easier to get OpenInkpot's X server running on our PocketBook devices than porting Xournal to run without X.