ShrinkIt takes bloated Adobe-saved graphic PDFs, runs them through Apple’s PDF renderer, and saves them back out, making many of them smaller without any quality loss.
Note, though: it’s not really for long complex PDF documents or bitmap images. It’s generally for simple PDF symbols and glyphs you might use in your apps, where saving space is critical.
Updated on Feb 16 2015
Note: Now requires OS X 10.7 or later running on a 64-bit Intel processor