There are more and more jquery chart and graph plotting that you can use in your projects. Most of them are free for personal and commercial use.
GraphUp is a very flexible and lightweight (only 4kB) jQuery (v1.4+) plugin to spice up your data tables. It displays data using color, bar charts and bubbles.
jqPlot is a plotting and charting plugin for the jQuery. jqPlot produces beautiful line, bar and pie charts with many features you can even add shadows and interact per drag&drop in the charts! It even automatically computes trend lines.