Changing Screenshot Formats in OS X
Keyboard shortcuts that can be used to capture screenshots in OS X:
Command + Shift + 3 will take a screenshot of the entire screen and its contents.
Command + Shift + 4 will show crosshairs that can be used in conjunction with the mouse to drag a square around the capture area.
Command + Shift + 4, then press spacebar will give you the ability to click on a specific window to capture only its contents.
Read the whole entry in Maclife.com.
ASCII characters on a Mac
If you are a new to mac, this post lets you know how to view a character map.