Well, you can do it directly from emacs without having to use AUCTeX: M-x compile and then change the Compile command: to the appropriate latex2html command. If you are going to be doing the .html rendering a lot, you can add the following code to the end of your .tex file:
% Local Variables:
% compile-command: "latex2html yourfile.tex"
From then on, whenever you load your .tex file the M-x compile command will default to the correct latex2html command.
You can bind M-x compile to a keyboard shortcut by adding something like (global-set-key "\C-xc" 'compile) to your .emacs file.