Use Excel - there was an ability to import live stock quotes and you can track the cost basis for taxes on individual lots, used to calculate aggregate dividend income or map it out on a dividend schedule. Look at online google spreadsheet - is not powerful like an excel, but if you want to keep a close watch on your buy/sell stats, it would be better than excel as always in plain sight on the tab in your browser.
Excel is the best.
I keep my track like that on daily bases.
Also i make several macros to help me with this so i dont have to import manually.
It have good chart you can create and its easy to handle so i will recommended it highly.