If you are looking for a convenient way to edit videos on your Android phone, XDA Developers has just released a killer app for you called VidTrim. With VidTrim you can trim video clips on your Android. You can also use it to play and delete videos and even save the trimmed version as a new clip or overwrite the original. It may not be 100% compatible with all Android phones as each manufacturer may use their own encoding format and the application cannot handle all of them. It has been tested on a Samsung Galaxy S.
It was developed by XDA forum member neoMJ, and he requests that any issues with other devices be reported back to him, presumably so he can enhance its compatibility across all platforms. You can download it from the Android Market or the following link. For more info or to download it directly check out this forum thread.
Source: XDA Developers