NEWBIE: a pretty simple search form problem

Hello!

I have a problem I have made a simple search form where you can select
a category, region and enter some free text.

My view looks like this:

<%= form_tag %>
  <table>
    <tr>
      <td>Category:</td>
        <td><%= select("search_item", "category",
JobCategory.active_categories.collect {|c| [c.title, c.id]}, {
:include_blank => true }) %></td>
     </tr>
     <tr>
       <td>Region:</td>
        <td> <%= select("search_item", "region",
Region.active_regions.collect {|r| [r.title, r.id]}, {:include_blank =>
true } ) %></td>
      </tr>
      <tr valign="top">
          <td>Free text:</td>
          <td><%= text_field("search_item","phrase", "size" => 40)
%></td>
         </tr>
      <tr>
          <td>...</td>
           <td><%= submit_tag(" Search ") %></td>
         </tr>
        </table>
  <%= end_form_tag %>

The search_item is just a simple class with the attributes category,
region and phrase.

Every example I have seen requires to create an object of a model but I
don't want to do this. I just want the code to fill my search_item
object with the correct values. Any ideas?