macos

Seems like the Automator solution doesn't work anymore.

So there is a simple one.

Install the CUPS-PDF module for OS X. This is a virtual PDF printer that looks like a "real" printer to the system, but creates a PDF file when you send a document to it.

https://bitbucket.org/codepoet/cups-pdf-for-mac-os-x/wiki/Home

If you make it as your default printer, then you just have to mass select all your files and do "Command" + "P" (shortcut). Mac OSX will open all files, send them to print in pdf, then close them = Simple and it works (on my Mac OS X 10.8.2 Montain Lion)

other tip :

"After you have installed the Virtual Printer using CUPS-PDF, there is a simpler and more powerful way to batch convert any set of documents to PDF files.

Use Printer Setup Utility to create a Desktop Printer icon for the Virtual Printer. After it is created, I put it in my Dock for easy access.

In the Finder, drag your file icons to the Virtual Printer icon. For Microsoft Word documents, Microsoft Word will be opened and instructed to print each document to that printer.

Unlike the Microsoft Word Macro method, you can do this for any other document created by any other program. As necessary, the Finder will open the appropriate application and tell it to print to the Virtual Printer.

There are two mild limitations to this general method.

(1) The files you drag to the printer icon need to be ones that the Mac knows what to do with (i.e. you can double-click to open it in some program on your Mac).

(2) The document's default "Open With" application needs to support the AppleScript command for Print. All well-behaved MacOS X programs do this. NeoOffice for example doesn't, and thus batch converting native NeoOffice documents does not work for this printer icon method."

Source (skip the macro part) : http://hints.macworld.com/article.php?story=20070315023808642