PS3 Slim is expected to be priced at $300 which includes Blu-ray, a 120GB hard disk, a DualShock 3 controller, and HDMI output with 1080p support. It's listed with an August 24 release date.
I think if you already own a Playstation 3 (like myself), it's not necessary to dish out another $300 for the slimmer version. Although there's more Hard Drive space on the slim version, the PS3 works fine with any USB External Hard Drive (some even goes up to 2.5 Tera Bytes). Also, nothing is mentioned about backwards compatibility or WiFi technology... So, I will be holding on to my over sized Playstation 3 until further notice.