This automator action works on almost all Word files (since that part is actually scripted), and basic Excel and Powerpoint files (.xls, .xlsx, .ppt, .pptx). Seems that Excel and Powerpoint are quite as scriptable as Word with respect to converting things to PDF, as half of the required objects are missing from their dictionaries…
(requires ASObjC Runner and satimage)
Unzip and move to services folder to enable for use in finder.
Browser: Safari 536.25
Operating System: Mac OS X (10.8)