Xournal is an application for notetaking, sketching, keeping a journal using a stylus. It is similar to Microsoft Windows Journal or to other alternatives such as Jarnal, Gournal, and NoteLab. It can also be used to annotate PDF files (highlight, underline etc.), and either save the annotations in a separate file, or export the annotated document as a new PDF file.
WWW: http://xournal.sourceforge.net/