This is a small javascript to make any vector layer into hexbins. It will use the colors from you vectorstyle, except for the transparancy that at the moment allways will be a fixed value. (This has to do with performance.)
A live demo of the output can be viewed at: http://spatialillusions.com/Demos/openlayers-hexbin/
This will turn on hexbinning on a layer.
this will turn off hexbinning on a layer.
Simple three clause MIT license.
It's made for Open Layers, so you will need that, otherwise none.
My contact details and other fun stuff can be found at http://spatialillusions.com/