The Conservation Assessment and Prioritization System (CAPS; http://www.umass.edu/landeco/research/caps/caps.html\) is a computer model for assessing ecological integrity and biodiversity value.
The CAPS Scenario Builder (this project) is a desktop application that will allow government officials, conservation groups and others to submit "scenarios" for proposed changes to land cover and infrastructure. The submitted scenarios will be processed by the CAPS computer model (not part of the CAPS Scenario Builder), and the results, detailing potential changes to ecological integrity and biodiversity, will be sent back to the submitters.
I uploaded the first version of the CAPS Scenario Builder to SVN today. In this version, the code is heavily commented (annotated), and may be helpful to those wishing to learn PyQGIS and/or PyQT.