Make a Google Map from a GPS file
Other map forms:
Google Earth KML/KMZ,
This form will automatically draw your GPS data (or KML/KMZ file, or plain text data in CSV or tab-delimited format) overlaid upon street maps and satellite imagery in Google Maps.
Please note that creating a map with a very large number of waypoints (or very long tracklogs, especially if speed or altitude colorization is enabled) can cause your Web browser to grind to a halt.
If you don't have GPS data and want to interactively draw on a map, use GPS Visualizer's "sandbox" to create your own GPX or KML file.