Shamelessly copy-pasted from the README file of the new plugin I released today:
Since form labels don’t use I18n in Rails 2.2 (I was too late in submitting the patch), we’d have to make due with a plugin.
Installation and configuration consists of 1 easy steps:
./script/plugin install git://github.com/iain/i18n_label.git
In your translation file:
en-US: activerecord: attributes: topic: name: 'A nice name'
In your view:
<% form_for Topic.new do |f| %> <%= f.label :name %> <% end %>
The result is:
<label for="topic_name">A nice name</label>
For more information about where to put your translations, read my post about translating ActiveRecord.