Gambling is a skill...
In Texas, I believe it is legal for participants to bet money on a pool game (or card game) with these two exceptions:
1) The "house" cannot take a cut of the money (which, as Macguy pointed out, being charged table time could be construed as such).
2) The venue does not serve alcohol. All gambling is illegal in an establishment that serves, or sells, alcohol. But, of course, one can buy all the lottery tickets one wants at the liquor store.
I also doubt that non-participants would be allowed to bet on the game. I'm sure there are other exceptions. It might also depend on local laws as well.