I recently came across 'romo' - a smartphone robot by Romotive (a recent start-up funded through Kickstarter). I love it. I think it's important. As you can see it's a plastic, tank-like little platform, with a panel and a strap for attaching your smartphone (iPhone here but Android works too). Ingeniously the wheels are controlled by output from the audio jack. Different sine wave frequencies applied to the left or right stereo channel trigger forward and backward motion and left/right turns (more info here). The rest is up to the phone, with it's various input (e.g. camera, WiFi, power sensor) and output (e.g. screen, speaker, and now wheels) channels. And the price: $99 (£62).
From what I've seen so far most people seem to be enjoying remote-controlling their romo from another smartphone. I'm more interested in developing the robot's autonomic behaviour. The 'Darwin' family of brain-based robots for example (Edelman et al., 1992; link) is controlled by a few tens of thousands of artificial brain cells and can explore its environment and see, approach, grab and evaluate objects in a laboratory setting. With the ability of a smartphone to run cloud apps (e.g. identification of objects using Google Goggles), generate and receive spoken commands (text-to-speech, speech-to-text) and reach a wide consumer and developer audience, interesting autonomous robotics suddenly seems tangible.