Very cool. I found a virtual piano with other options. It even lets you play via your keyboard and not just 'one note plunking' that most restrict you too. You must check this out. Run your mouse over the keys to see the great response. You can also "click to activate keyboard control" on the left side of the control panel and you can go to town. Now this isn't like a normal piano when in keyboard mode but you'll get used to it once you "Z" is the low and "P" is the high. From there, you just have to learn an alternate way of tickling the virtual ivory!
There are drums, etc... as well to compliment your new creations. I just added several mixers (new mixer added 5/2/10 at bottom of post) so you can get a beat going while plunking away on the boards.