Hmmmm. I can say that it depends on what level you wish to work at.
I for example, have been working at the regional theatre level, working about 50 weeks a year. For the past three years, I have made anywhere from $30,000 to $60,000 a year.
If you do broadway, you can imagine yourself making $60,000 - $100,000 a year.
If you tour on a production contract, your will make roughly the same.
If you do industirals as well, you could start making $500 - $2000 a day, but those jobs are few and far between.
Hope that helps.