I much prefer ETF's but have also scoured the net this past year in search for some free backtesting. There are plenty of screeners out there. Yahoo Finance always seemed ok by me. Years ago I used a site called something like "Pitbull investing". It screened according to the CANSLIM IBD type criteria. Worked ok back in the late 90's. It always seemed to come up with some stock winners. I think it's a pay site now.
The only free backtesting I've found is a little beta site that backtests TA. This site lets you use only various custimizeable moving average and/or bollinger band strategies for major stocks and popular ETF's. Even some leveraged ETFs. Not very comprehensive but its free and gives nice results in either graphical or tabular form with buys and sells. Just that it's uses only very specific TA signals---moving averages, bollinger.
Oops, almost forgot, Fidelity has a limited free TA backtesting site: