Android :: How To Run Application Source Code?

For all of you android devs out there that have the Android simulator running on your computer, you know that there are a few built in apps that are already installed on your 'phone'. I had an idea for an app that would utilize a function that is already being done in the spare parts app that comes already installed. I went on to the android developer site, dug through the source code files, and found the spare parts app, and am now trying to set it up so that running it from eclipse on my machine actually runs the app in the simulator.

In other words, I want to be able to make changes to and adjust some of the things in that app for my own needs. But it won't compile, because of a number of different errors. How do I get that source code running on my local machine? Is there some special trick that I just don't know about? I thought that if I could get the source code than the rest would be easy, but it isn't being too easy.