These days many portals provide online charts to do technical analysis. Many of these tools are quit advanced. There are also software available which can produce charts from trading data. These data can be pulled from server or can be made locally available.
Most of the stock exchanges have their website where they host the software to plot charts. There are many portals including Yahoo and Google where you can find online charts.
There are many professional charting software available in market. Now a days there are even good open-source software available for creating charts. We will list these software in this section.