By default, if you connect the camera to the Mac via the included USB cable AND power up the camera (that's an important step), then the Mac will usually launch iPhoto. You can actually control what the Mac launches or configure it not to launch anything at all.
I configured my Mac not to launch anything at all and I use Aperture to import, manage, and adjust my photos.
You can manually launch a photo app and tell it to import and that will work too.
This assumes the Mac sees the camera attached to the USB port. Are you connecting the camera directly into the Mac or are you using a USB hub?