It depends what you mean by penny stocks. If you mean OTC/BB/Pink Sheets then I cannot see how you could trade these on an on-line site.

A non US resident can trade US penny shares through a London broker if there is liquidity and you are trading dematted stock.

Before anyone says "no you can't" I can assure you that you can because I have done it!

I have tried E*Trade, SureTrade and few other websites, but they all demand an American citizenship. Is there a trusted way to trade Penny stocks from outside the U.S.? I've been trying to find something through research, but so far nothing! Does anybody know how? Or, if it's possible?