It's a law, federal I believe, that any gambling jackpot (slots and video poker) $1200 and above requires a W2-G. There are allocations whereby people can split jackpots and get separate W2-Gs from the casino.

How this applies to winning a poker tournament, I don't know.

I also know that if you win money in a promotional event such as a drawing or free promotional slot tournament, that if the total of such prizes in an individual casino adds up to some minimal amount (our tax acct. friend should know), you receive a 1099 for misc. income. I don't know if there is a way to divide a large score legally for such a prize as there is with the W2-G.

I don't know how the prizes for poker tournaments are handled, I could ask a friend of mine who has taken some top prizes in AC tourneys.

If they are handled with a 1099, some extra consideration should be given to the person taking the paper. For example, I was involved a while back in a promotional game that lasted for weeks where some skill was involved. A group of us were partnered up and it was agreed that if one among us was the top prize winner (100K), he or she would get enough extra to cover the tax bite.