Install Python 2.7.1 side-by-side with Apple-supplied Python

I have just downloaded the Python 2.7.1 DMG from Python.org. I have seen suggestions to get ActivePython, but I would prefer the one from Python.org.

1. If I just run the mpkg installer inside the DMG, accepting all defaults, will it live peacefully with the Apple-supplied Python?
2. If I type python in Terminal, which one will I get?
3. In Terminal, how do I specify to run the Apple-supplied Python? What about the Python I installed myself?
4. What are these talk about setting the PATH when installing a different Python version? I understand that the Python installer will just set it up automatically. But I still want to peek under the hood. I know how to do this in Windows (Environment Variables). For Mac OS X, how do I tinker with the PATH?

I might as well try these out myself first, but I'm new to the Mac. Python is quite a complicated installation, writing files to different folders and configuring OS settings like PATH. TrashMe or AppCleaner might not be very effective with uninstalling Python if ever I want to go back to a clean slate. Therefore I want to gain clear insights to my questions above.