Quote from http://news.cnet.com/8301-17938_105-10312144-1.html:
The Slim is hitting stores September 1 in North America and will cost $299 (or for those who live in other regions, 299 euros or 29,980 yen). Hirai says the device has the same features and functions as the "old" PS3 but is 33 percent smaller, 36 percent lighter, and comes with a 120GB hard drive. (See photo comparison here).
Sony says that to achieve the new form factor, the internal design architecture of the new PS3 system has been completely redesigned--"from the main semiconductors and power supply unit to the cooling mechanism."
The PS3 Slim is powered by a new 45nm version of the Cell processor, which runs at the same speed as the 60nm processor in the "old" PS3 but is smaller and more energy efficient. According to company reps, power consumption for the Slim has also been cut to two-thirds, "helping to reduce fan noise," which is important.
Kaz Hirai unveils the PS3 Slim in Cologne, Germany.
On the cosmetic front, this model has a textured surface finish that gives the PS3 a fresh, casual look that the company hopes will make it more appealing to a wider audience (read: casual gamers). As previously rumored, the PS3 logo has undergone a redesign and Sony's changing the PS3 brand name from "PLAYSTATION 3" to "PlayStation 3" (we've actually been calling it the PlayStation 3 for a while).
Like the 80GB and 160GB models, the 120GB PS3 Slim has built-in Wi-Fi and two USB ports (sorry, Sony didn't add IR). You can also upgrade/replace the hard drive without voiding the warranty, though Sony has moved the hard drive from the side of the unit to the front for "easier access." (To remove the hard drive, you simply unscrew the screws). The one feature missing from the Slim is the ability to install another operating system (i.e., Linux)--Sony is doing away with that feature.
With earlier PS3s, you could prop your unit up vertically or lay it down horizontally. Out of the box, the Slim is only designed to be used in a horizontal position, but Sony will sell a $24 stand that allows you to stand it up vertically.
In making the move to the PS3 Slim, Sony will be upgrading the firmware to 3.00 and phasing out its legacy 80GB and 160GB models, selling them for $299 and $399 respectively.
John Koller, director of hardware marketing for Sony Computer Entertainment America, says they've been able to run down inventory of older models, but he didn't have the best answer as to why someone would buy an old 80GB model over the new 120GB Slim. "Some people want a unit right away and they may like the look of the old unit," he said. "People will have their reasons for wanting one."