Modal form example
This is an example of how I'd use jQuery-UI dialog form to implement a modal form which handles errors (in response to http://stackoverflow.com/questions/6374664/rails-and-modal-jquery-dialog-form).
If you're looking for the rails 3 example it's still here: https://github.com/ramblex/modal-form/tree/rails3
Use the following to get started. After downloading the app run:
bundle bundle exec rake db:migrate bundle rails s
Go to http://localhost:3000/articles and the modal form should come up when you click on the 'New article' link.