Actually PrintConductor (free) can batch print more than just pdf -- it uses the native programs to do the main work.
PrintConductor can batch print 16 document types: PDF, DOC, WRI, WPS, RTF, TXT, XLS, PPT, PPS, POT, VSD, DWG, DXF, SNP, HTM, HTML.
PrintConductor supports any printer installed on your computer and provides you with instant access to the settings of the specified printer.
Add documents to the list using drag & drop, Open dialog box or auto-scan a specified folder and its subfolders for documents of needed types. Sort documents by name or type, preview before you print, and/or print any document(s) from the list.
A progress bar keeps you informed of the '%complete' status of the job. And, the job can be easily cancelled at any time in processing.
A bunch of other free pdf tools can be found here as well: http://www.esnips.com/web/PDFTools
ps. If you have $60 bucks to spare (ouch!) you can buy a batch & print pro
, which is an excellent batch printer with some additional features, most notably showing page counts, which can be quite useful.