Shows how one might set a default will_paginate link renderer in a rails application

application_helper.rb

module ApplicationHelper
  # This method is overriding the view helper provided by `will_paginate`
  def will_paginate(collection_or_options = nil, options = {})
    options, collection_or_options = collection_or_options, nil if collection_or_options.is_a? Hash
    options.merge! :renderer => YourCustomLinkRenderer unless options[:renderer]
    super *[collection_or_options, options].compact
  end
end