Having a backer and paying taxes

I know this topic has been discussed many times over but I really couldn't find exactly what I was looking for in the search. If someone has a link to help me out please feel free to post it.

For the last two years I have been playing online poker as my primary source of income, though it has only been since my graduation in May that I have used it as a full time job. While in school I was able to build a bankroll from 300 dollars to 10,000, but I used most of this to have fun/pay off debts from studying abroad/pay rent etc and after graduation was left with a bankroll of 3,000.

Since then I have been taking graduate classes and playing 2/4, and I am making enough money to survive and live on my own but nowhere near enough to also build a bankroll.

Today my father, who has watched me win over 500,000 hands and a long period of time, started to ask me about what I could make through a backing deal where he gave me 10,000 to work with.

The only real concerns he has are with the legality of online poker and paying taxes. I believe he can give me a once a year gift of 10,000 tax free. Now say I take this gift before Jan 1 and make it into 100,000 by the end of next year. Then I give him his 50,000 share. Do I have to pay taxes on this 50,000, give it to him, and then he would have to pay taxes on what he actually receives? Or do I not declare the 50,000 and let him take care of declaring/paying taxes? Also, he has an upper managment job and is concerned about the best way to declare any winnings. Would it be wise to treat it like a small business on next years return, or should he treat it as if he had won 50,000 at the lottery?

Lastly, to the best of my knowledge it is not clear whether or not online poker is legal or illegal in the US. I guess his biggest worry is that he takes his cut of winnings, pays taxes, and then gets in trouble for participatingin /aiding an illegal activity. Has there been any clarification on the law as of late?

Sorry for the length of the post, but any information would be great.

To cut off some comments and questions...
Right now I work as a high school coach and am in the midst of getting a bartending job, so please don't tell me how I could just get a job and build a bankroll myself. Poker and coaching and grad school take up most of my time.

Also, I have hardly any knowledge on this subject, so if any of these questions are elementary I apologize.

Thanks again,

Jon