Thanks for all the advice,
while in principle XNView should work, it unfortunately split up every page into several ones so I could not scale them to 600 x 800 pixels.
So far I found NitroPDF which can quite nicely crop PDFs but whenever I resize them to 600 x 800 every programs just adds margins (empty space) instead of scaling the content. I think what they do is just scale according to the original aspect ratio, while I want them to just scale until the content fills 600 x 800 no matter what.
Last edited by gxxshock; 01-26-2009 at 02:26 PM.