According to a recent post on Techcrunch, Google is opening up access to Map Maker, a tool allowing modification of map data, adding or editing roads, points of interest and other Google Map features where Google has limited map data, to India. It had been open only to smaller island nations previously.
For those not blessed by Google/Yahoo/Mapquest, OpenStreetMap was previously the only option to allow citizen-cartographers to add and edit map features. Because it is open to everyone, the information can be old, missing and/or incorrect. For most points in the United States, the level of detail is pretty good but some other countries I checked were pretty blank besides main roads. The data is Creative Commons licensed and free for use without any restrictions so if your mashup is localized to areas with good detail, OSM might be a good alternative to Google Maps. Its site is more barebones and focused on interacting with the map and not all the secondary services Google Maps supplies.
With many areas of rapid development and re-development in the United States that could benefit from Map Maker, I think it’s a matter of when it will get opened up the the US and not if. I just hope that OpenStreetMap’s community doesn’t lose contributers and that they do it for the love of cartography and don’t just target the bigger name.