Joining the seemingly never-ending stream of free Google tools for Web developers, allow me to present the Google Chart API:
The amazing thing about Google Charts is not that it’s free (there are other free charting options) and not that it allows anyone to add slick-looking charts on their Web site (there are already hundreds of ways to do that), but how trivially easy it is to use. All charts are created using a simple URL call. For example, here is the URL to generate the chart above:
If you look closely at the URL, you will notice something unusual—there is no account or login information specified in the URL. That’s right, the Chart API is completely anonymous, which means you can create as many charts as you need, on the fly at any time, without ever registering with Google.
There is one simple limitation: only 50,000 accesses per day per IP address. This may seem like a serious limitation for high-traffic Web sites, but keep in mind that the IP requesting a chart belongs to the end user, not your Web server. Very few users will ever run into this limit.
The utter simplicity of the Google Chart API makes charting so astonishingly easy that I predict a huge uptick in the number of charts on the Web.