ScreenShotFormatX... If you want to change the output format of screenshots (command/shift/3 or 4), you can do that very easily with ScreenShotFormatX. The choices are BMP, GIF, JPEG 2000, JPG, PDF, PICT, PNG, PSD and TIFF.
What's new in ScreenShotFormatX
Version 1.2: Now universal binary. Now Mac OS X.5 Leopard compatible.