Let me start off by saying I am not a Mac person. I have an iPhone, but, thats about all I can say. As I was trying to jailbreak and recover some images off my moms phone this weekend I needed to take screenshots of what I was doing so I could back track if needed. Unsure of how to do this I Googled up this post:
How To: Take a Screenshot With the iPhone
It boils down to holding the Home button (the big circle under the screen) and the Sleep button (the on-off button) at the same time. In case, like me, you want to double check based on those Mac names, look at this link: