MOSS or WSS?

If MOSS, then there is a document  conversion service that can convert Word documents  into SharePoint pages. The user  uploads the document and then using the document's dropdown menu requests the conversion. Typically the converted document is moved to another library for user access.

msdn.microsoft.com/en-us/library/ms518493.aspx

msdn.microsoft.com/en-us/library/aa979484.aspx

office.microsoft.com/.../HA101575371033.aspx

If you have MOSS Enterprise Edition then you can also display Excel files and InfoPath forms in a browser.