OpenOffice imports into Draw, then you export as pdf. It's a bit slow and some documents just don't load, in my experience. On the odd occasions I've needed to alter something, I've extracted the page with pdftk, edited it in Gimp, exported, and re-inserted; but it's not an experience I'd recomend! If you try pdfedit, let us know if it's any good.
Rather belatedly, I've looked at Wikipedia. There's an article "List of PDF software" that seems to cover everything!
Last edited by DavidMcCann; 10-30-2012 at 01:49 PM.