LG VX-8100

I know that a bunch of people have asked this question and im hoping that someone has the answer. I want to take the video, but i want it to be longer than 15 seconds. I know people have asked this before but i have looked at them and have never got an answer from them. so if someone could give me a clear and simple answer cuz im still learning this phone, that would be great. just want to be able to take a video with the phone and taking a video longer than 15 seconds. thankx