Some software I have been using related to the tablet:
CellWriter http://risujin.org/cellwriter/ - Excellent trainable, multilanguage handwriting recognition and onscreen keyboard. I wouldn't bother with any others, but I've listed a few here:
Onscreen keyboards (all available in apt repositories):
klavier - Onscreen keyboard with tray icon for KDE.
gok - For Gnome, I haven't used it..
onscreen - python-based, probably works in KDE and Gnome.