There's xpdf which includes the pdftotext binary.
Pdftotext converts Portable Document Format (PDF) files to plain text.
On Linux there's a installer available. It seems that it also comes in the poppler-utils package. On OS X you could install it using Homebrew (install that first) and then use
brew install xpdf
which will download the source files and compile it for OS X. After that, just use it like:
pdftotext your_pdf_file.pdf
which will generate a plain text file. There are a couple of options as well, check out man pdftotext for more details.