I have played with this before and the banks themselves are playing the same game, just with multi million pound solutions. I know one guy that has superfast internet and a software package which costs him something like 200k and he seems to make very good money.
If you want to play the markets avoid the short term plays and play the long term bets against the markets or major currency pairs, that way you will avoid the issue of not getting in and out in time. Alternatively and probably more wisely, spread your investment across multiple unit trusts and let the experts do it for you.