R help - Mar 2012 - Predicting confidence intervals for fitted values for non-linear regression

Hello,

I am interested in calculating the confidence intervals for fitted values for
non-linear regressions. For instance, I have used the nlme package to generate
my non-linear model.

summary(lme(myvariable~age+age.sq+age.cu, data=my.matrix, random=~1|Name))

I would like to use the model generated from the data in my.matrix to predict
the confidence intervals for new ages. Someone posted a question similar to mine
a few years ago, but the website someone sent in response to the question is no
longer in use. I will paste their question below because I think it is clearer
than mine.

Thank you for your help,
Kate

"I am interested to calculate confidence interval for fitted values in
general for non-linear regressions. Lets say we have y=f(x1,x2,..xN) where f()
is a non-linear regression. I would like to calculate a confidence interval for
new prediction f(a1,..,aN). I am aware of techniques for calculating confidence
intervals for coeffiecients in specific non-linear regressions and with them
then to calculate confidence interval for the predicted value. ...

Any references to the literature or R packages would be very welcome."