Launching On-screen keyboard in Windows XP
 

Windows XP comes with a built in on screen keyboard.

• Start
• Run.. and type OSK
• Graphic keyboard comes on

To create a shortcut on Desktop

• Right click on desktop
• New -> Shortcut -> type OSK
• Next -> Finish

Hmm... that's a good way to do it, however you can also do this by
Start > All Programs > Accessories > Accessibility > On-screen keyboard.
I'm guessing this might be a bit more helpful, because if you need to access the on screen keyboard chances are that you can't use your keyboard properly.