EAN  Completely lame.  
(Version 1.3)

HOMEWORLD  "Modified the code to improve the application."

Well, yeah... but please try to be more vague next time.

Seriously, what's the point? The OS has had this capability since... I can't even remember how long. That's how long it's been.  
(Version 1.2)

MORJOVY  i will never understand developers who make "just another" program which mac os already has built-in...  
(Version 1.0)

ZZAMBONI  In addition to what IanWeir wrote, there's the included Grab.app (in /Applications/Utilities/) for grabbing screenshots of portions/whole screen, timed screenshots, etc.  
(Version 1.0)

IANWEIR  This functionality is already built in, from Tiger-onwards for sure, and I'm pretty sure quite some time before that.

Just press command-shift-4 to get the crosshairs (for a selection), and if you would like to take a screenshot of a window, press the spacebar at this point and the cursor will turn into a camera and you can take screenshots of windows.

If you add control to the previous key combination, it will put the screenshot in your clipboard instead of on the desktop.

You can also use command-shift-3 and command-control-shift-3 to take normal screenshots & put them into the clipboard, respectively.  
(Version 1.0)