conroller:

    unless params[:upload][:datafile] == ''
      @datafile = params[:upload][:datafile].original_filename
    else
      @datafile = params[:upload][:datafile]
    end


    @movie = Movie.new(:name => params[:upload][:name],
                          :filename => @datafile,
                          :description => params[:upload][:description])

form:

<%= error_messages_for 'movie' %>

<p><div class="form_label">Name</div>

	<div class="form_field"><%= text_field 'upload', 'name' %></div></p>

<p><div class="form_label">Select File</div>

	<div class="form_field"><%= file_field 'upload', 'datafile' %></div></p>

<p><div class="form_label">Description</div>

	<div class="form_field"><%= text_area 'upload', 'description', :size => "40x20" %></div></p>