
This is very easy to say and very difficult to do as every organization has a different version of what a project looks like in Excel.
However, the Data Loader does this.
http://usermanual.clarizen.com/#data-loader
http://www.clarizen.com/appsmarketplace/item/Data-Loader.html
http://www.youtube.com/watch?v=jIaS7QtG-gw