[R] need 95% confidence interval bands on cubic extrapolation

[James Salsman]

Dear R experts:

I need to get this plot, but also with 95% confidence interval bands:

   hour <- c(1, 2, 3, 4, 5, 6)
   millivolts <- c(3.5, 5, 7.5, 13, 40, 58)

   plot(hour, millivolts, xlim=c(1,10), ylim=c(0,1000))

   pm <- lm(millivolts ~ poly(hour, 3))

   curve(predict(pm, data.frame(hour=x)), add=TRUE)

How can the 95% confidence interval band curves be plotted too?

Sincerely,
James Salsman

P.S.  I know I should be using data frames instead of parallel lists.
This is just a simple example.