mapping widgets and OpenLayers

I just heard about the OpenLayers project, and I thought I should 
forward this link, for anyone who's interested in mapping APIs and 
wasn't aware that this existed:
  http://openlayers.org/

I've never looked at Dojo's GoogleMap and YahooMap widgets, and I don't 
know anything about mapping APIs myself, so I don't know if/how 
OpenLayers would fit into the picture, but I wanted to mention it.

~ skinner