I only know FoxIT Reader, that can also edit PDF files. The basic version is free, though I believe there are some watermarks or similar, when you save your PDF with it (only use it for reading so far). There is also a pro version, without the watermarks, but yeah.. that one isn't free.
In any case - much faster in opening/scrolling huge PDFs than Adobe Reader in my experience. I see there is actually an editor application out now:
http://www.foxitsoftware.com/pdf/editor/Otherwise, Mr.Google says:
http://www.nitropdf.com/free/hammer/index.htm which seems to be a web based fully functional PDF editor.
At work we have some kind of a virtual printer plugin, which makes pretty much everything into an image-pdf and .doc files into proper text based PDF. I don't know where this came from or what vendor it is, unfortunately, I'm sure there is something similar flying around on the web, though.