onscreen keyboard

System Pref > Language & Text > Input Sources > Check Keyboard & Character Viewer. Then in the menu bar at the top you'll see a new icon which you can click and Show Keyboard Viewer. If there isn't an icon you can check in the Input Sources pane that the 'Show Input menu in menu bar' is checked.

Yes, click on your system preferences and the click on language & text then click on the input sources tab make sure keyboard & character viewer is checked then hit the short cut key on the or turn on the show input menu in menu bar and the bottom of the screen.