Hi!
I own a Cybook since two years and was bugged that there is no easy-to-use open-source software for cropping pdf files so the last couple of days I hacked something which might be usefull for other ebook users. Since its written in Java should run under Linux/Windows/MacOSX.
You can download the application from sourceforge:
http://sourceforge.net/projects/briss/
So if you want to make the best out of your 6 inch try BRISS ;-)
If the name offends your religious feelings I sure can think of a better one.
Waiting for feedback,
laborg