Just found out another very powerful API from google again. This is the "Google Chart API".
By using this API, you just need to submit all the necessary infor to the google url and get back al the cart as you specify.
For example img src="http://chart.apis.google.com/chart?cht=p3&chd=s:hW&chs=250x100&chl=Hello|World" alt="Sample chart" / (you should include the <> as normal HTML tag in order to apply this chart) will generate the following chart
There are still alot of interesting tools to be discover.
You may go to here for more infor