You can import videos from your cell phone to iMovie using Image Capture. This is best way to avoid using iPhoto or iTunes if you are on a shared computer.
1. Plug phone into USB. Use back of computer rather than keyboard.
2. If your computer automatically opens iPhoto and/or iTunes, close them.
3. Using the magnifying glass icon in the top right-hand corner of the main bar, search for Image Capture. Click to Open.
4. Cell Phone should show up on left-hand side and photos and videos in the middle.
5. Scroll to select only the ones you want to download. Use Shift + Click to select multiple clips.
6. Change Import To: to Desktop.
7. Click Import.
8. When it is done, close Image Capture.
9. Open iMovie by selecting the Star icon on the bottom application bar.
10. In iMovie, select File>Import Movies Select the video clips from your desktop and click Import. This will take some time based on how length of video clips.