Google's My Maps tool lets you import a Google Sheet and have the data from that sheet displayed as placemarks on an interactive map. Watch this video that I created to learn how you can create a map based on data in a Google Sheet.
Felt is a relatively new multimedia mapping tool. In your Felt account you can upload a CSV or Excel file and have the data within the spreadsheet distributed as placemarks and or polygons on a map. After the data is initially loaded you can then customize the design of your map by altering the color, size, and shape of the placemarks and polygons. You can also customize the size and color of the labels on your map after the spreadsheet data has been imported onto your map. Watch my video below to learn how to display your spreadsheet data on a Felt map.
Heat Map Tool is a tool for easily creating heat maps or incident maps from a CSV file. To create a heat map all you need to do is upload a CSV file then specify your desired display attributes like scale, colors, and opacity. You can edit the display attributes of your map whenever you like. If you're wondering how to create a CSV file you can do so by exporting from a spreadsheet in Google Documents or exporting from an Excel file. Click here for directions on exporting from Excel. The free version of Heat Map Tool allows you to have up to 100 data points on your map and up to 500 hits per day on your map.