Just a quick reminder for myself: if you're doing a form that is uploading files, remember to add :multipart => true to the form tag, e.g.:
[source:ruby]
< % form_for(:product, :url => products_path(@product), :html => {:multipart => true, :method => :put }) do |f| %>

< % end %>
[/source]

I came across this today when trying to find an easier way to present a six-part form in a Rails project - a tabbed interface system built upon Prototype (an integral part of Rails). Called Control.Tabs it makes tabbed interfaces a synch to do: simply add an unordered list containing links to the blocks containing your to-be-tabbed content, and add a line of JavaScript to start the ball rolling - that's it!