Rightly said, first you have to learn what is technical analysis for which traderji is a good place then depending on what type of trader you are, then you can choose from many technical analysis softwares available which suit your need the most.
By the way I had used Investar which is good, ChartAlert which is far better than Investar but Investar provides Intraday option whereas ChartAlert is an EOD software.
Now I am settled for Amibroker though I am still using Trial version I will buy it very soon, this is the best software for me.