A: It may be a good idea
Depending on where you live, mother nature may be kind enough to wash your solar panels for you-- periodic rainfall may be sufficient to keep your panels soot & bird poop free.
But if you live in a more arid climate, it's a good idea to wash your panels down every few months, or when you notice that they're looking a little dirty. A good quality soft brush and a squeegee with a plastic blade on one side and a cloth covered sponge on the other coupled with a long extension can make for the perfect tools allowing you to stay on the ground. Use a hose with a suitable nozzle to allow the stream of water to reach the panels.
Energymatters.com has some more useful tips on keeping your solar panels clean & firing out maximum output. Of course, as the author notes, always take proper safety precautions if you're going to clean your panels yourself: http://ow.ly/CewR300g86l #MythMonday