Image-free CSS Tooltip Pointers - A Use for Polygonal CSS? | Filament Group, Inc.
http://www.filamentgroup.com/lab/image_free_css_tooltip_pointers_a_use_for_polygonal_css/

At Filament Group, we build elegant communications and interactions that help people understand, work, and collaborate effectively across a variety of media - from web sites to wireless, to interactive exhibits and print.