Google usually hands out free devices to the developers that attend its workshops, but at Google I/O next month it'll be asking them for phones, not giving them away. The search company is starting "Android for Good", collecting unlocked and working Android handsets from those that no longer need them, and then donating them to projects all over the world.
Those projects include various data tracking and monitoring initiatives, which use the Android phones to input and crunch data:
"A small team collected Android devices from Googlers around the world and organized their donation to groups including Grameem’s AppLab Community Knowledge Worker Initiative in Uganda, Save the Elephants in Kenya, V-Day in the Democratic Republic of Congo,VillageReach in Mozambique, VetAid in Tanzania & Kenya, and UNHCR in Central Africa." Zi Wang, Google
If you're headed to Google I/O 2011 and have a spare device - that's unlocked and fully-functional - then you can drop it off at the Android for Good booth on the third floor of Moscone Center. Google is also apparently looking into how it could extend the scheme to cover people not in the US and not attending a developer event.