The Logitech QuickCam Sphere is the latest, coold webcam design solution from Logitech offering cross-platform compatibility, excellent image quality and face-tracking abilities in one very sleek package.
Here its quite impressive list of features:
Mechanical pan-and-tilt technology and automatic face-tracking software
(The mechanical pan and tilt feature allows the webcam to physically turn 128 degrees side-to-side (for an almost 180-degree horizontal view), and 54 degrees up-and-down (for an almost 90-degree vertical view)
Make eye-contact thanks to unique 22 cm stand
Digital zoom
Built-in microphone
Shoot photos at 640x480 resolution
Works with both PC and Mac OS® X
Works with both USB 2.0 and 1.1
Video capture: up to 640 x 480 pixels
Still image capture: up to 1280 x 960 pixels (interpolated)
Frame rate: up to 30 frames per second (with recommended system)
2-year guarantee
System Requirements:
PC:
Windows® 2000, Me, XP
400 MHz Pentium® II, Celeron®, AMD Athlon processor (500Mhz+ recommended)
64 MB RAM (or minimum OS requirement whichever is higher)
200 MB free hard drive space
CD-ROM drive
16-bit colour display adapter
Windows® compatible sound card and speakers (full duplex sound card recommended)
Mac:
Mac OS® 10.1.5+
128 MB RAM
Available USB port
Mac OS® 10.2 requires Power Mac® G3, G4, G4 Cube; iMac®; PowerBook G3, G4; iBook®; or eMac computer, at least 128 MB of physical RAM and a built-in display or a display connected to an Apple-supplied video card.

Indicative cost: EU 150
More info about the Logitech QuikCam Sphere here.