Any LDP author is welcome to use the WikiText. It is on the LDP database, http://db.linuxdoc.org. You will need to have an account on the database. If you don't have one yet, you can request one from me by email. Send me your full name (as it appears on your documents), username and password, and I will set it up for you, probably the same day.
Once you're logged onto the database, click "My Documents". If you don't see a list of your own documents (only), I messed up. :-)
Click the document you want to edit. You will see a page that shows the meta-data we have for the document. Also on that page is a link to WikiEdit. Click it, and you're on your way.
Click "Preview" to see how your document will appear on the LDP (except that it will be rendered in a single page).
Click "DocBook" to see the raw DocBook that WikiText generated from your text.
Click "Save" to save your changes to the database. You can also add a "comment" to it, for future reference.
Click "Version History" to see a record of all the changes you've made to the document.