I am willing to start stock trading (buy,sell, short, cover). I would like to do this for US stock exchanges "only". I need an online broker that has best service terms/commissions for Finland. Can you recommend one to use from FINLAND - but with english interface.
Moreover, suppose I make some money (x euros) and lose some money (y euros). How would the tax filings go?
Any other advice on the subject (except I have to be VERY careful as this is a risky business?

)
Thanks.