I have a coolpix s52 and cannot install nikon transfer software into my mac 10.5

Download the most recent version of Nikon Transfer (and other programs) from
http://support.nikontech.com/app/answers/detail/a_id/61

You might want to consider NOT connecting your camera to your computer. The best way to download pictures from your camera to your computer involves removing the memory card from the camera and plugging it into a card reader (either built-in to the computer or connected via USB or FireWire). This is likely to be faster than connecting the camera to the computer, and won't run down your camera's batteries.

Once the card is plugged in, it will appear to your computer as a removable drive. You can use the operating system's drag&drop facility to copy pictures from the card to the computer's hard drive, the same way you copy any other files. Or you can use iPhoto or Nikon Transfer or any other photo cataloging program.