I have heard that the 3.1 firmware gives the iPhone 3G (and the iPod touch) video editing capability so, I decided to check it out. Indeed, the firmware update does allow the iPhone 3G to edit video (without jailbreaking mind you). Below is how it works.
You will first need someone to email you a video file (I had Doug email me one he took with his iPhone 3GS). Once you have received the video, 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. You can then go into your Camera Roll and select the video.
After selecting the video, you are 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 have the option to trim the original video or save the trimmed potion as a new clip in your Camera Roll.
So, even though you can’t take video on your unjailbroken iPhone 3G… I guess you can at least edit it. I’m not really sure there is a huge purpose to this feature but, there you go.
I only tested this on an iPhone 3G but, it is said to work on an iPod touch running 3.1.1 as well.
-- Post From My iPhone3g