This is it, the mythical drag-and-drop multi-column grid has arrived. Gridster is a jQuery plugin that allows building intuitive draggable layouts from elements spanning multiple columns. You can even dynamically add and remove elements from the grid. It is on par with sliced bread, or possibly better. MIT licensed. Suitable for children of all ages.
Gridster is currently written as a jQuery plugin, so you need to include it in the head of the document. Download the latest release at jQuery.