attachment in mail

How to do the attachment in mail like the yahoo and gmail does?

<% form_tag(depot_help_desk_path, :method => :post, :multipart =>
true) do %>
  <div>
    <fieldset>
      <legend>Helpdesk formulier</legend>
      <div style="width: 300 px;">1. Ik werk met de volgende browser:</

      <%= radio_button "helpdesk", "browser", "Internet Explorer"
%>Internet Explorer<br/>
      <%= radio_button "helpdesk", "browser", "Safari" %>Safari<br/>
      <%= radio_button "helpdesk", "browser", "Mozilla Firefox"
%>Mozilla Firefox<br /><br />

      <div style="width: 300 px;">2. Ik werk met de volgende computer:</

      <%= radio_button "helpdesk", "os", "windows" %>Windows<br />
      <%= radio_button "helpdesk", "os", "mac" %>Mac<br />
      <%= radio_button "helpdesk", "os", "linux" %>Linux<br /><br />

      <div style="width: 300 px;">3. Mijn gebruikersnaam is:</div>
      <label id="label_right"><%= text_field 'helpdesk',
'user_name', :class => "txtfield", :size => 20 %></label><br /><br />

      <div style="width: 300 px;">4. Mijn e-mail adres is:</div>
      <label id="label_right"><%= text_field 'helpdesk',
'email', :class => "txtfield", :size => 20 %></label><br /><br />

      <div style="width: 400 px;">5. Het probleem is op de volgende
datum opgetreden:</div>
      <label id="label_right"><%= text_field 'helpdesk', 'datum', :class
=> "txtfield", :size => 20 %></label><br /><br />

      <div style="width: 300 px;">6. De URL waar het probleem zich
voordoet is:</div>
      <label id="label_right"><%= text_field 'helpdesk', 'url', :class
=> "txtfield", :size => 20 %></label><br /><br />

      <div style="width: 300 px;">7. Bestand toevoegen:</div>
      <%= file_field 'helpdesk', 'file', :class => "txtfield", :size =>
20 %><br /><br />

      <div style="width: 300 px;">8. Het originele bestand heb ik
bijgevoegd:</div>
      <%= radio_button "helpdesk", "bestand", "ja" %>ja<br />
      <%= radio_button "helpdesk", "bestand", "nee" %>nee<br /><br />

      <div style="width: 550 px;">9. Graag zo volledig mogelijk
omschrijven (stapsgewijs) wat het probleem / je vraag is.</div>
      <label id="label_right"><%= text_area 'helpdesk', 'text', :cols =>
"70", :rows => 20 %></label><br /><br />

      <div style="width: 550 px;">Hartelijk dank voor het invullen van
bovenstaand formulier. Klik op versturen en wij streven ernaar binnen
5 werkdagen te reageren.</div>

      <div><%= submit_tag "versturen", :onClick => "", :id => 'disable-
me' %></div><br />
  </fieldset>
</div>
<% end %>

  def ticket_with_attachment(browser, os, email, user_name, datum,
url, file, bestand, text, sent_at = Time.now )
    @subject = 'Helpdesk verzoek: ' + user_name
    @body = { :browser => browser, :os => os, :user_name =>
user_name, :email => email, :datum => datum, :url => url, :bestand =>
bestand, :text => text }
    @recipients = "xxx@xxx.net"
    @from = "xxx@xxx.net"
    @sent_on = sent_at
    unless file.blank?
      attachment :body => file.read, :filename =>
file.original_filename
    end
  end

That's working code from one of our apps. Not very nice looking, but
should do.
Important parts are the file_field in the form (all others are just
text or radio buttons)
and those lines in the ActionMailer delivery method:

unless file.blank?
   attachment :body => file.read, :filename => file.original_filename
end

which will attach the file to the mail

Thank you Muller I will try it and let you know the oucome.