They definately crawl index and index .pdf's as I get a lot of traffic from those http://www.google.ie/search?hl=en&c2coff=1&q=.pdf&meta= I think that Word Documents are indexed however to tell you the truth, all my experience is with SEOing pdf's
There are 13 main file types searched by Google in addition to standard web formatted documents in HTML. * Adobe Portable Document Format (pdf) * Adobe PostScript (ps) * Lotus 1-2-3 (wk1, wk2, wk3, wk4, wk5, wki, wks, wku) * Lotus WordPro (lwp) * MacWrite (mw) * Microsoft Excel (xls) * Microsoft PowerPoint (ppt) * Microsoft Word (doc) * Microsoft Works (wks, wps, wdb) * Microsoft Write (wri) * Rich Text Format (rtf) * Shockwave Flash (swf) * Text (ans, txt)
There is a firefox plugin that has an option to "see"/save this files as html file. So if a browser can do that, why not an SE? Or am I wrong somehow?
If your search turns up a non-HTML file, such as a PDF file, Google includes the option in the listing to "View as HTML".