After hearing that the Apple iPhone 3G may suffer from a memory leak which causes applications to become slower over time, I looked at my iPhone 3G and wondered "How do I turn off my iPhone 3G?", and "How do I restart my iPhone 3G?"

Fortunately turning off or restarting an iPhone is pretty easy ... once you know how to do it. Here are the steps to follow to restart an iPhone:

1. Press and hold down the sleep/wake button on the top-right corner of the iPhone.
2. Keep holding the button down (about five seconds) until you see a slider button labeled "Slide to power off".
3. To turn off the iPhone, move the slider across the screen. Or, if you don't want to turn it off just press the Cancel button at the bottom of the screen.
4. When your iPhone is off and you want to turn it back on, press down and hold the sleep/wake button until the Apple icon appears on screen. (This takes just a second or two.) A few moments after the Apple icon appears your iPhone will be restarted and you will see your home screen.

I don't know if there really is a memory leak, but this morning -- immediately following the 2.0.1 system upgrade -- I had problems placing a call with my iPhone 3G, and I found that restarting the iPhone fixed this problem.