I second the Confirmed.
Just got a Zi8. I use the internal USB and connect it to my MBP. Two mounts are established in Finder: "no name" (the SD card, which doesn't have a name) and "arcsoft sw" the internal software for Windows only (??).
In iMovie, go to File - Import Movies, and select the name of your SD card mount (for me, it's "no name"). Then, drill down into the DCIM folder and find the .MOV files, and begin importing.