Researching Company Salaries

Is there somewhere where you can get a basic idea of how much certain companies pay for certain positions within the company?

I'm thinking about applying for a position in a company, but I have no idea what the salary would be. The job posting doesn't even give a hint as to how much it pays, yet asks the salary I'm expecting. Like a game of chicken or something.

This isn't a position I could just look up on Salary.com. Very specific position in the company that I think I'm more than qualified for. If the salary is too high, I don't want to low-ball myself. If it's too low, I want to apply for a senior position which would pay more.

Closest thing I could find was Vault.com, but it appears to be a pay site.