What is the most effective way to organize .psds for a large scale application project

I'm working on a project at work where we are building out a full scale application. Its going to span a 2 year period. Ive been naming and dating psds. I'm still having a hard time staying organized. I'm starting to design a design library and I am planning on attaching all my psds there in order to organize everything. That in itself is a pretty massive undertaking for one person as I am already working on the project as it is.

In the mean time I figured I would see how other people organize their psds and see if there is some way that I haven't thought of yet. Any help would be much appreciated.