Career InfoNet -> http://acinet.org/
"America's Career InfoNet is a resource for making informed career
decisions to support a demand-driven workforce investment system."
Using this link, You can know salary, necessary skills/education, and detailed work activities.
Occupation Information
->http://acinet.org/occ_rep.asp?id=1&nodeid=2
For example, the salary comparison between programmer and chief executive is below.
Salary - Programmer $63,000 (10%-90%: $37,200 - $101,000)
Salary - Chief Executive $141,800 (10%-90%: $59,200 - $145,600+)