Permalinks are good but they often generate urls that may be excessively long and not keyword optimised. I’ve developed a plugin that optimises the permalink slug to boost the seo potential of your urls. http://www.york-newyork.com/seo-plugin-wordpress-urls/
I’ve just created a plugin to do this. Take a look at the anouncement: http://wordpress.org/support/topic/94617
and download the plugin at:
http://www.york-newyork.com/seo-plugin-wordpress-urls/
cheers,
mightymouse