Launch iMage Capture from your applications folder.
1. Connect your phone to your computer.
2. Select your phone in the Devices list at the left of the Image Capture window.
3. From the “Connecting this [device] opens” pop-up menu, choose nothing.
If you don’t see that pop-up menu, click the “Show device settings” button in the lower-left corner.
Not sure if it will work for everyone, but i guess worh a try if you are as frustrated as i was
this process worked on my mac, just to prove, i tried the steps again, and it worked.
it's the same process outlined by whosten, but with an additional tweak.
1. open image capture
2. connect the phone (imovie will open - one last time) close the import dialog, and imovie app. on my Mac, imovie crashed,
3. change the auto-open app for the device to image capture application)
4. if you like to keep image capture to open ( i actually dont mind the image capture to open), do nothing
5. connect phone again, select do nothing when connecting this device (same as step 3 in the earlier post.