beem, i didnt read the site that was posted above, but i know one thing, government salaries are also based upon grade. you can have the same job but move up in grade and you get paid more.
my uncle works at Northrop Grummond in VA and he has had the same job for 8 years now, but his grade has jumped 4 levels in that time span. Each grade has a min and max salary level. Northrop is a government contractor and uses the government system of grades. My uncle is gonna be changing jobs soon, but his high grade, for the job title, is gonna help him get an even higher paying job now.
that might be kinda confusing...
if you have questions Pm/email me