http://bit.ly/billsbookIn this video tutorial I look at how to use your piano's sustain pedal (sometimes, wrongly, called the "loud pedal").
You can use the sustain pedal both to help smooth out your playing and for some interesting effects. However, it's really important that you don't over use the pedal, or you riskyour piano playing sounding messy and even discordant. In general, it's a good idea to release and re-push the sustain pedal between chord changes to prevent dissonances carrying over into the changed harmony.
You can also use pedal to sustain complex or "jumpy" melodies, but, again, it's important to make sure you don't overuse it.
Using the sustain pedal is one of the areas where it's really important to listen to your piano playing while you practice - because playing the piano is relatively mechanical, it's easy to "switch off" and not really play close attention to the sound you're making.
The sustain pedal also highlights the differences between different types of piano, and between digital pianos and acoustic ones. Again, it's all about listening to yourself and the instrument you're playing and using the pedal accordingly.