http://www.eagle-of-liberty.com/writeinone/index_en.php

WriteInOne works on Mac OS X Tiger 10.4 only.

One-Window !
WriteInOne allows to edit your documents in only one window.

Unlimited Documents
You will be able to open an endless number of documents.

RTFD Integration
WriteInOne allows to edit RTF & RTFD documents.

Word Integration
WriteInOne allows to edit Microsoft Word Documents.

Web pages
WriteInOne also allows to quickly edit HTML and PHP documents.