yeah, terra nova has some kind of deal with Real tick. I've never used either so can't reccomend.
As far as direct access goes, you are going to get filled at the screen price. So when you hit the button on your computer, it goes to your broker and your broker sends it to the exchange.
Now, if all that moving at 186.000 miles per second isn't fast enough for you, then you can pay a couple of grand as month for direct access to the exchange.
But, with 56k dial up and AOL, you are going to get filled at the screen price anyway.
And, if you use limits, you can send your order in by carrier pigeon
and no matter how fast somebody elses connection is, they still have to wait in line behind you if you decided on the limit price before they did.