The PS3 Slim has been announced by a very unlikely source: K-Mart. On their homepage they're running the above graphic, pronouncing a new PS3.
The graphic links to this PS3 Slim product page, which seems to imply that the Slim will launch at $300 on August 24th (that's next Monday!). Sony has a press conference later today from Games Com, and that should reveal all about the Slim. Until then, I guess you can go ahead and pre-order if it's something you're interested in.