Ushahidi is an open source web application for information collection, visualisation and interactive mapping. It allows people to collect and share their own stories using various mediums such as SMS, Web Forms, Email or Twitter. Ushahidi which is written in PHP (5.3 or greater recommended) and MySQL, allow you to make smart decisions with a data management system that rapidly collects data from the crowd and visualizes what happened, when and where.
Ushahidi applications can give you better idea of how powerful this tool can be, such as it is used in the WaterTracker project in Afghanistan as a dashboard for monitoring water points across the country, using community feedback, which saved USAID and the government time and money. Another case study is joint initiative to monitor the 2013 elections in Kenya, they deployed Ushahidi to enable citizens, civil society, election observers, law enforcement agencies and humanitarian response agencies to monitor election incidents in real-time and take action where necessary.
You can download Ushahidi from the official website or get it from the github repository. Installation details are available in the github repository also, also you may check the project wiki for documentation and other issues.
Curious to see the product capabilities, check Ushahidi v3 demo (user : demo, pass : testing)