And now there is Google Charts, a way to let Google's servers draw your charts for you. Here's some examples:
The url http://chart.apis.google.com/chart?chs=600x300&cht=v&chd=t:20,100,0,0,0,0&chdl=Times+I+am+happy|Times+I+am+wearing+pants yields:
If you want to create some graphs in your webpages, clearly this is the way to go. And instead of linking to Google's servers, you could also save the image to your own webspace, obviously.
Check out all the documentation on Google Chart API.