[R] Nonlinear Regression

[Liam Brown]

I'm wondering what packages exist to implement nonlinear least squares
regression in R other than 'nls'. Are there packages which implement
methods to estimate the optimum values of the parameters which do not
use the Gauss-Newton algorithm e.g. use Nelder Mead. In particular,
I'd be interested where this is done where the methods of the plinear
algorithm are also used (the initial step using the projection
matrix). If these don't exist why is the Gauss-Newton algorithm
considered sufficient?

Also can I implement the Levenberg Marquadt algorithm in nls?

Regards
Liam