After a very long search, I finally found a full-featured program that allows me to edit PDF files.

Qoppa PDF Editor offers a lot of features including:

- add highlighting,
- add comments,
- crossout-text,
- extract text embedded in the file,
- scan to PDF (can scan and insert directly into a PDF document),
- modify pages,
- add or remove pages from a document,
- add hyperlinks
- and other etc. etc. features

The program is written in JAVA and there are versions for Linux, Mac and Windows so you can use the same program on WinXP and Linux if you are dual booting.

I tested it in my Ubuntu 7.10 and found all its features to be fully compatable with Adobe Acrobat -- when I created highligting or notes in Qoppa PDF Editor and then opened it inside Adobe Acrobat 7, all of the highlighting and notes were intact! Great! Perhaps more researchers and students can switch to Linux now that a good PDF tool that allows highlighting and comments is available!

Check out Qoppa Software at http://www.qoppa.com/psindex.html