[R] glm gamma scale parameter

[WILLIE, JILL]

I would like the option to specify alternative scale parameters when
using the gamma family, log link glm.  In particular I would like the
option to specify any of the following:

1.  maximum likelihood estimate
2.  moment estimator/Pearson's 
3.  total deviance estimator

Is this easy?  Possible?  

In addition, I would like to know what estimation process (maximum
likelihood?) R is using to estimate the parameter if somebody knows that
off the top of their head or can point me to something to read?  

I did read the help & search the archives but I'm a bit confused trying
to reconcile the terminology I'm used to w/R terminology as we're
transitioning to R, so if I missed an obvious way to do this, or stated
this question in a way that's incomprehensible, my apologies.

Jill Willie 
Open Seas
Safeco Insurance
jilwil at safeco.com