Making the iPhone play a Video in the background is actually possible. So while, you type and SMS or Browse through photos on Coloris the video would keep playing in the Background.
A loop hole in the firmware allows this on any iPhone firmware up to the current v2.2.1. The iPhone sure is capable of some good MultiTasking. Here, are the steps:
Making a Video play in Background
1. Go to the iPod App
2. Play any video file
3. Press the home button to exit the iPod app and return to the home screen 4. Press the sleep button to turn off the screen 5. Now, Double tap the home button 6. Press > Play
7. Slide and unlock the screen
You will now hear the Video playing in the background, while you can browse around and do anything on the iPhone!!