The PS 3 Slim is released today at Gamescom as rumoured and it will be on sale on September 1st for 299 USD
Update: I juz went to EB games in Melbourne Central earlier today and can confirm that they will have the PS 3 Slim in stock by September 3rd for AUD 499.
. It will have no backward compatibility, 2 USB ports instead of 4, tactile buttons instead of touch, matte logo instead of gloss, about 50% slimmer but does not come with HDMI cable (which is a big boo) and you cant install a Linux OS on it. It will have a larger HDD as standard which is 120 GB.
It is now available for pre-order in the US (once again sadface) at major retailers and websites such as Amazon.com, Kmart, and FYE. Germany, Saturn is selling it as well.
All in all beside the apparent size drops, the current crop of PS 3 to me is still a better buy, especially at the current price. Unless the lack of space is making you think of the slim and you like the look of it, there is little reason to buy the slim.
Here are some links to round-up this PS 3 slim summary