As a byproduct of my work on www.campzero.com, I released my first ruby on rails plugin called acts_as_permalinkable on github athttp://github.com/smsohan/acts_as_permalinkable
A comprehensive documentation is given at the github page. If you ever need to use search engine friendly urls or permalink like this blog, you may consider using the acts_as_permalinkable plugin. It takes less than 3 minutes to add the permalink feature to your rails model!
Get started by the following and you are free to contribute!
script/plugin install git://github.com/smsohan/acts_as_permalinkable.git