I'm not convinced about the access thing, though. http://www.interactivebrokers.com has decent looking connections for non-crazy prices, and their brokerage fees are good too.
I don't think you'd be able to do a pure HF strategy using it, but it's possible a strategy based on volatility trading could work maybe(?)
Volatility trading is more math-focused, but requires discretionary trading as well. Its less automated, and requires more specialized knowledge than other strategies. Volatility strategies aren't run by random people coming out of school or other industries. They are almost always run by a trader with a very well developed back-end including a quant (who is trained in volatility modelings - not as easy as the books lead you to believe) and still a very sophisticated trading system with access to both the options exchanges (which are unwieldy) and "normal" equities exchanges.
Its all possible, but can you make a living at it? Its a big maybe. Can you actually make more than your normal job or even a fraction if you were with a well endowed quant fund? No way. Not unless you have been in the industry for a long time.
The mechanics:
IB wants to buy X at $100, you want to sell $X at 100. Normally your order would be routed to the exchange and so would theirs. Both would go to the back of the queue: if Foo/Bar placed buy/sell orders at $100 before you, they get filled first.
Instead, both you and IB get to bypass the queue by trading directly with you. The only real cost to you is that this probably incurs some latency.
Don't get me wrong: These firms do provide liquidity, which is great for anyone trading in the markets, but if you are going to try to play these firms' game of running liquidity providing strategies or even stat-arb style strategies, on their home court you just aren't going to be very effective. That is unless you are running something totally new. (Side note: I knew a guy trading MBS based off of an obscure NY state housing law. The strategy was totally unique, and ran like clock work. If you have something like that, than you could be marginally successful. He was making like 300k a year off of 60k in capital).