I made an input handler that will allow for this for one of my C# games, although it's for an XBOX controller, but the concept is similar, and it has a few more useful features. Let me find it.
EDIT: well, I can't find the USB drive that the project was on, but this is the basic code:
float timeSincePressed;
bool doublePressed;
public void Update(GameTime gameTime)
{
doublePressed = key.Pressed && (doublePressed || timeSincePressed < 0.2f);
if (key.Pressed)
timeSincePressed = 0;
else
timeSincePressed += gameTime.ElapsedGameTime.TotalSeconds;
}
That should work, tell me if there are problems.