If you use the screen capture feature of OS X (command-shift-3 or command-shift-4) you will have to deal with items on the Desktop.  Every time you take a screen shot a new "Picture" appears on the desktop.  That's okay for the first few pictures, but if you are taking a series of pictures (say around 50), when you get done taking pictures you have a heck of a mess on your Desktop.

The solution is to change where the screen shots are saved.  Your can do this with Onyx or TinkerTools, or you can do it by hand by firing up the Terminal and doing these two commands ...

$ defaults write com.apple.screencapture location <path to folder to save images to>
$ killall SystemUIServer

Make sure you have typed in a valid folder path.  If you dont' you'll get a warning and no screen shot will be saved.

from TUAW