Ruby on Rails: how do I use a default placeholder thing in a select_tag?

Question

 <%= select_tag(:services, 
                       options_from_collection_for_select(Service.all, :id, :name))%>

And it displays all the ser

Answer 1

<%= select_tag(:services, 
               Service.all.collect { |c| [c.id, c.name] }.
               insert(0, "Select a Service"))%>

As answered for the question, this is for Rails 2.3. For Rails 3, see Prathan Thananart's answer.