[R] built in variance component function for lm

[David Springate]

Hi,

Is there a built in function for calculating variance components from  
a standard linear model using lm?

I know you can do this using lme for ML and REML, but I can't find a  
method for doing this for least squares.
I am looking to calculate variance components for the interaction  
between two factors, family (random) and treatment (fixed) on a trait.

Thanks,

David Springate