Look out Devantech, there's a new kid on the proverbial block, the robotics-block, that is. While the ultrasonic sensor line from Devantech has turned into a staple for many hobby robots, it looks like there might be another viable contender. Check out the Ultrasonic Range Finder from Maxbotix, which is listed for $24. A FAQ and datasheet on the sensor are available on Maxbotix's website. The specs on the device say it can range from 0 to 6.45 meters (0 - 256 inches), and outputs in either serial, analog, or PWM signals.
PS. Maxbotix or Devantech, if you're listening, how about sending some of your stuff our way for reviews?