OpenCV is a popular computer vision library ported to many platforms.  The Robot Vision Toolkit uses OpenCV for its face detection language extension.

The Roomba iCreate is a fantastic robot base.  The Robot Vision Toolkit can be used to communicate with the base using a serial port or virtual com port. Check out the example see files for controlling the Roomba and some of the project done with it.

The Robot Vision Toolkit helps you build smarter robots.  Using RobotSee and the advanced language extensions, anyone can build a robot that uses computer vision, mind control, speech recognition, .....

Chumby based Robotics

Android based robots.  This group supports robots built using android phones and tablets.