>_>, its just a modeling program, you dont need a stellar pc to make a movie like AC, they made it on normal pc's just like ours, its just the actual rendering of the CGI takes place at render farms, else it would take months for the movie to render ( maybe even years >_>).

and yes most likely maya was used, could've been XSI also though ( xsi cost 18k$ , so maya is cheap )

Dont think making a cgi movie is easy though :P