Custom share button for LinkedIn

I have a box with buttons at the footer of all my posts to share (http://jonjensen.com/blog/?p=1487 for example). All the buttons work, but I can’t figure how to automatically generate the URL, blog title, and a first paragraph in the PHP.

LinkedIn says this is possible: http://www.linkedin.com/static?key=developers_widget_shareonlinkedin

Anyone know what code I can put in to auto-generate the meta data?

Seriously stumped.