You can see the US Government's official descriptions of all sorts of occupations (Dep't. of Labor), plus what you can make in various parts of the US, at
www.salary.com
I'm not sure where you can get career testing done (I presume you mean for free), but take a look at
www.vault.com for some leads. You can also check your local phone book, look up Career Counseling.
Best of luck to you!