Google Visualization API and Chart Tools
http://code.google.com/apis/chart/interactive/docs/index.html

The Google Visualization API allows you to create charts and reporting applications over structured data and helps integrate these directly into your website or on a Gadget. With the Google Visualization API, you can access structured data–created locally in your browser or retrieved from supported data sources in a simple tabular format. You can also implement your own data source as Visualization API data source and enable any Visualization-compliant visualization and/or application to access your data. The format is amenable to use by reporting, analysis or chart applications. You can thus visualize the data and/or add new functionality to applications, such as Google Spreadsheets. This has been added to the tools section of Research Resources Subject Tracer™ Information Blog.