For some useful theory for estimation and planning of projects, Eli Goldratt wrote amazing content in the book "Critical Chain" which is an easy to read novel.
Should you find yourself developing this tool further, these books will give you an edge that most other tools lack -
Should you find yourself developing this tool further, these books will give you an edge that most other tools lack -
http://www.amazon.com/Critical-Chain/dp/B002LHRM2E/
http://www.amazon.com/Be-Fast-Gone/dp/B004THZ9VK/
http://www.amazon.com/CCPM-3rdEd/dp/1608077349/