From a word document or a PDF file, is there a way to link to a
particular bookmark within a seperate pdf document?  I know how to
link to an adobe file from a word doc, or from one pdf file to
another, or to a specific link within a single pdf file, but is there
a way to link to a specific link within one pdf file from a seperate
document?

Are the files both on a local computer? Do you want to use on Windows
(with IE) as the default?

Assuming that the two PDF files are not local, then just use the
nameddest Open Paramter. Example:

http://www.mydomain.com/pdf/pdf2.pdf#nameddest=Chapter3

For more information, see:
http://partners.adobe.com/public/developer/en/acrobat/PDFOpenParams.pdf
(with a complete list of OpenParams)

Note: This techique doesn't work locally using the file protocol in IE.

If not, get a copy O'Reilly's PDF Hacks and check out the PDFHacks
website (http://www.pdfhacks.com). There are plugins and tools to be
able to do what you want.