Alexis Madrigal throws a link our way while talking about GPS-enabled iPhones:

With Steve Jobs' announcement that the iPhone 3G will have geolocation built-in, plenty of people are excited about finding good restaurants near them or worried about the privacy implications of that

But the new capability could be adapted by a different, unexpected crowd: citizen scientists taking the real-time environmental pulse of cities and suburb.

One requirement of this data-gathering effort would be maintaining the integrity of the data input. GPS eliminates the need to accurately report location data, which is a major area of human error. With Apple putting devices with these capabilities into the hands of more and more consumers, scientists could discover a huge untapped data-gathering resource if they can churn out cheap sensors that can communicate with the iPhone.