Due to the recent 3.1 iPhone OS update, the iPhone 3G and iPod Touch are now able to edit video just like the iPhone 
3GS. Both devices still can’t record video, unless jailbroken, so this may not come as a big tool for most people.
To get it to work, first you must get someone to email you a video file. Once you have it, you can open the email and select the arrow on the lower menu bar. This will give you five options: Reply, Reply All, Forward, Save Video and Cancel. Once you select Save Video, the video will get saved to your Camera Roll.
Go to the Camera Roll and select the video, you are then able to watch the video and edit it. To edit a video, tap on the timeline at the top of the page, you can then drag your finger to the start and end points on the video. When you select trim, you then have the option to trim the original video or save the trimmed potion as a new clip.
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