Hi there
Macs are pretty idiot proof, unfortunatly you not being an idiot can probably break it

It is not showing in disk utility and is not kicking iPhoto into action.
1. Do you actually have photos on the phone?
2. Is the USB cable working?
3. Is the USB port working.
With the phone plugged in. If you go into the Apple menu and select "About this Mac" you should get a little ox of info up. There is a option to see more info. Select it. You should have an offer on 'hardware' and near the end is one named USB, if you select this it will tell you what is attached to your USB ports. Does it detect the phone?
Have you tried different USB ports?
Are you going through a hub - including the USB on the keyboard if there is one, or are you using a USB on the Mac?
I have had occasional issues with cameras not liking the hub ports but being fine on the main ports - not sure why.
R