Kotaku has posted all of NBA Jam's secret characters (so far), including their ratings.
"Who's a better dunker, Obama or Clinton? Can Tim Kitzrow, Mr. Boom-Shakalaka, throw down on Mike D from the Beastie Boys? And was it really necessary to give all of the Republicans an 8-out-of-10 rating in "steal"?
There are seven secret teams that are unlockable in NBA Jam on the Wii through codes entered either at the first screen (the one that says "Press A to start") or where you enter your initials before picking your team. When you correctly enter a code, the game gives you a quick sound. To see the teams, press Plus at the team selection menu. For the directional codes, be sure to hold the Wii Remote vertically."