This looks pretty interesting:
Dubbed "PSX," the device features a built-in 120 GB hard drive and recordable slot-loading DVD±RW/-R drive, as well as TV tuner and Ethernet port. For expansion, the PSX will include USB 2.0 support and a Memory Stick slot. Sony will also include a connector for its upcoming PSP portable entertainment device.
This also appears to be a separate device from the new revision PS2 already announced. More details (and pictures!) can be found in this PDF.