PDFs created by OS X's built-in "Save as PDF..." option on the print menu have a tendency to bloat. OS X's PDFs are often a lot bigger than the ones you get from, say, Adobe Acrobat. (Not the "reader", the actual creation program.) Fortunately, the same PDF menu that allows you to print to PDF also allows you to create a smaller, compressed version of your material. Instead of selecting "Save as PDF...", try selecting "Compress PDF" instead. You'll produce a compact version of your PDF file.
To test, I printed TUAW's home page in both normal and compressed versions. The savings? Almost 10% smaller file size.