Mobile devices are getting greener all the time. The best cell phones and smartphones contain fewer toxic materials and are more easily recyclable. But what about while they're in use -- can they do green good in your hand?

Nokia and Segway inventor Dean Kamen think so. They're sponsoring a $25,000 prize for the best new mobile applications "that enhance the use of mobile devices in real-world scenarios." Prizes will be awarded in three categories, including an "Eco-Challenge" category looking for "mobile solutions that help consumers make sustainable choices such as reducing their energy consumption or carbon footprint."

The possibilities in this category are pretty wide. Nokia says "Developers who submit for this category will be building tools to help people take care of the environment - from charger reminders to mobile learning applications, from navigation info to recycling tips."

So, do you think you can program the next big "green app" for mobile devices? If so, get to it. Entries are due December 15th.