Rails 2.3 has a good solution for multi model forms. But there is not much examples of  how to use accepts_nested_attributes_for with has_one relation.

Assume that we have a Book model which has one Author.

Controller :

View:

No special action is needed for create method of BooksController,  attr_accessible is not necessary for Book model. Just don’t forget to add the second parameter (@book) of form_for and build your nested object (@book.build_author).