cheat sheets.

Install:
>> ./script/plugin install
http://svn.techno-weenie.net/projects/plugins/permalink_fu/
>> piston import http://svn.techno-weenie.net/projects/plugins/permalink_fu/

Modify table:
>> ./script/generate migration add_permalink_to_article
>> add_column :designers, :permalink, :string

Model:

class Article < ActiveRecord::Base
        # title is the field name you want to convert to a permalink
        has_permalink :title 
        # you can also specifiy a different permalink field in your database by
        giving a second paramater
        # has_permalink :title, :my_permalink_field

        # we now add the to_param method which Rails's routing uses
        def to_param
              permalink
        end         
end

Convert old titles to permalinks:
>> Article.find(:all).each(&:save)

Hackish find(id):
>> @article = Article.find_by_permalink(params[:id])

# in your route file
map.connect 'article/:permalink', :controller => 'article', :action => 'view'
# in your views when linking
link_to "View #{article.title}", {:controller => 'designer', :action => 'view',
:permalink => article.permalink}
# then in your controller you can use
@article = Article.find_by_permalink(params[:permalink])

Reference: http://www.seoonrails.com/even-better-looking-urls-with-permalink_fu