Thought it was worth bringing this over to a new thread of its own. No-one has reported receiving a Next VIP invite yet, but I clicked on the registration page:
and entered my details (as I do usuall get a VIP invite), and it let me register my slot for Weds at 5pm.
The confirmation email detailed the following info about the online pdf listings and instore sale, although the pdfs don't seem to be posted up on their website yet - probably because the registration page has only been live for an hour or so:
The Sale will be available for advanced viewing at http://www.next.co.uk/sale from Monday 16th July 2007 and is available for you to preview.
Alternatively, the Next End of Season Sale starts in stores from 5AM on Saturday 21st July, except selected London stores which start the sale on Friday 20th July (please check your local store for details or visit http://www.next.co.uk/stores).