OpenLayers!

GRASS GIS (Geographic Resources Analysis Support System) is an open source, free software (FOSS) Geographical Information System (GIS) with raster, topological, vector, image processing, and visualization functionality. Used for geospatial data management and analysis, image processing, graphics/maps production, spatial modeling, and visualization, GRASS is currently used in academic and commercial settings around the world, as well as by many governmental agencies and environmental consulting companies. »

MapBox makes it easy to design beautiful custom maps, and fast to integrate them into websites and mobile applications using Open Street Map data.

ArcGIS is geographic information system (GIS) software for visualizing, managing, creating, and analyzing geographic data. Using ArcGIS, you can understand the geographic context of your data, allowing you to see relationships and identify patterns in new ways.

You can use RepresentMap to setup a website that visualizes your local startup community on a custom Google map.

TravelTime platform is an API that analyses location data by minutes, rather than miles. The API can create travel time maps, sort location search results by travel time and generate full end-to-end routing information. Travel cost and CO2 calculation data also available within this API.

Google Maps API is a collection of APIs that enable you to overlay your own data on a customized Google Map. You can create engaging web and mobile applications with Google’s powerful mapping platform including satellite imagery, street view, elevation profiles, driving directions, styled maps, demographics, analytics and an extensive places database.

Easily Work With Location Data In Spreadsheets. GeoSheets lets you get comprehensive location lookup by state, neighborhood, and more with dead simple functions.

Resources to create compelling map-based web applications. Bing Maps SDK, Bing Maps API (geocoding API).