Google is working with the University of Washington on an open source field data collection tool called the Open Data Kit (ODK).
Open Data Kit is a free and open-source set of tools which help organizations author, field, and manage mobile data collection solutions. ODK provides an out-of-the-box solution for users to:

Build a data collection form or survey;
Collect the data on a mobile device and send it to a server; and
Aggregate the collected data on a server and extract it in useful formats.

In addition to socio-economic and health surveys with GPS locations and images, ODK is being used to create decision support for clinicians and for building multimedia-rich nature mapping tools. See the list available tools, featured deployments, and implementation companies for more examples of what the ODK community is doing. We welcome and encourage participation from the user community.

According to Spatial Sustain blog, the system is being put to work in many developing nations for mapping and data collection efforts, including in Mexico, Tanzania, and Brazil.