aka Mac OS X 10.5, actually, because there's one simple change that Apple's made to the way the phone interacts with the Mac that's a huge boon for those of us that actually take pics with the iPhone!
Plug in your phone, and even if you don't want to sync it with your iTunes software you'll find that if there are photos on the phone that Image Capture can now see 'em and grab them for you:
What I've done is set up a new 'iPhone Pictures" folder in my Pictures directory (instead of the default "Pictures, Movies and Music folders", choose "Other..." then navigate to your Pictures directory and click "New Folder" on the lower left).
Click on "Download All" and you've just accomplished the world's easiest cellphone photo sync on your new Macintosh!
If you are running an earlier version of Mac OS X, then I suggest that you let iPhoto do the work: start that up before you plug in your phone and it should see the phone and offer you the opportunity to download your pictures into an iPhoto "roll".