There are a couple possibilities to solve this. If the document isn't heavily formatted, you should be able to rename it from a .doc file to a .rtf file, and open it in Wordpad. Once it is opened in Wordpad just re-save it as a Word .doc file. You will likely lose a considerable amount of formatting using this method though.
This link:
http://www.metacafe.com/watch/110765..._password_doc/
Has an interesting trick to try and find your password by opening the file in Notepad.
Otherwise you're looking at a hack program to find or remove the password. Here is one example:
http://www.petri.co.il/word-password-recovery.htm, but use any hack at your own risk.
Hope this helps.
-SW