A bit late, but nevertheless:
Here’s the link (pdf) to the full list of salaries paid to MLS players for the 2008 season. Beckham earns the most, but the gap between him and the other million-dollar club members is as vast (he earns twice as much as Blanco, and 4-5 times as much as the other 3 $1 mil+ players) as the gap between the million-dollar club and the ‘regular’ MLS players.
It also highlights an interesting point – while some people have recommended wage caps as a method of dealing with spiraling wage costs in the Premier League, wage caps have the undesired effects of chasing good players away to leagues that pay more. And if you do end up implementing caps, it effectively cripples football to the extent that loopholes need to be invented to work around the problem and bring in marquee players to build teams around.
Question for readers – do the MLS clubs have enough money to pay free-market wages?