Scripts to make emacs, pdfsync and xpdf work together.
Forward/Inverse from tex to pdf never quite seem to work out of the box. These scripts aim to ensure that you will be able to do forward/inverse search from emacs to tex. Pdfsync is used for the synchronization.
pdf2oo converts pdf to odf. It creates an image for each page, allowing to overlay drawings and text and export it back to pdf. Handy for rewiews of scientific papers. The closest thing to a free pdf editor, "almost" an openoffice pdf import filter.
PdfRipImage is a program to automatically extract images from PDF documents and convert them to a format of your choice (such as JPEG or TIFF). It runs on UNIX-like platforms and requires utilities from netpbm and xpdf.