If you want to instruct in the US you will need to get your FAA Commercial - which means 250 hours TT. In addition, you will need to get your FAA IR beore you can become a Certified Flight Instructor (CFI)
To become a CFI you have to take another two written tests and prove you can teach in a classroom before a check ride with the FAA dude.
(I had a 9 hour oral exam before he was satisfied and let me fly - do it with a designated pilot examiner instead of the FAA and you should get an easier time of it, although the FAA like to do as many as they can.)
If you get your PPL you'll be about 10% of the way there. If you've got a truckload of money and free time, you'll probably be a CFI in six months give or take. Then you'll be qualified to make less money than the Ugliest girl serving you at your local Hooters.
Good luck!