By the way NicBDA the E-Bow .. is the pick you use to play the string .. isn't it ??
Sort of, its is used instead of the pick. In my last post the last bit is a link to the item at a large US music store (available from other places too).
It creates a magnetic field that causes the string to vibrate (as long as they are ferrous, so it won't do squat to a nylon string). As long as the string is in the field it'll vibrate playing what ever note is fretted (or open). You can do neat things like swells by moving the bow towards the string then away again (sounds like a violin being bowed), sweeping arpegios ect.
I first saw it when I went to a Vinnie Moore guitar clinic here in Bermuda. He used it to great effect (though in all fairness he has a bit of skill to begin with
)
It's just another tool in the box that you may not use all the time, but when you need it, it does it's intended to do.