data here in PDF). The figure above shows the distribution of "2012 Guaranteed Compensation" for MLS players, with the lowest paid players on the left and the highest on the right (there are 549 players in the dataset). You can click on the figures in this post for a better view.
You can see that it is a rather skewed distribution. The graph below shows the salaries of those players who make less than $1 million (which is almost all of them), and it is still skewed.
The graph below shows the distribution of compensation against the league total, which is almost exactly $90 million. It shows that 50% of the league's compensation goes to 492 players and the other 50% of compensation goes to 47 players.
this excellent online calculator). It shows that the MLS has a level of inequality that might be comparable to Haiti or Bolivia, and much higher level of inequality than found in men's professional tennis. It would be interesting to compare across sports, countries and leagues, but that would necessitate a big data collection effort.