PDF Tools
PDF/AI input
ill2svg
Perl script shipped with Inkscape today. Can only handle the older postscript based ai files?
ai2svg
pdf2svg
pstoedit
Translates PostScript and PDF graphics into other vector formats. Needs to call a PostScript (or Pdf?) interpreter like Ghostscript. SVG plugin available as binary only.
ps2svg
SVG driver for Ghostscript. Not available?
Ghostscript
Xpdf
Poppler
A PDF rendering library based on Xpdf.
UberConverter
pdftk
Scribus
PDF/AI output
ps2ai
Postscript script shipped with Inkscape today. Generates the older postscript based ai files?