The western world needs to somehow get rid of our taboo on income. In a lot of eastern European countries, paychecks are just laid out on tables. Everyone knows what everyone makes.
There have been countless articles that talk about how there isn't a huge pay disparity between men and women in skilled jobs, and articles like The Confidence Gap (Salon) that show that when disparity does occur, it's simply of women not being confident enough to ask for what they deserve.
(On a side note, I hypothesize if you could objectively measure confidence and then compared incomes to confident vs non-confident people in their field, the pay distribution would be low to high among them, regardless of gender. That's difficult theory to prove though).
At larger companies, you have pay grades listed and everyone in Active Directory has a pay grad associated with them (BlueCross orgs are like this). So you can actually look up, within a $8k range, what everyone around you makes, and it pretty much stays accurate until you get up to the VP/board positions.
I wish more companies had transparency on this, but I feel like income transparency is going to stay limited to the public sector.