Don't have one on Yahoo, but there's a fanstar pick'em league here: http://www.fantasybaseballone.com/madness/site8248/
Oh one more thing when i register do i have to put a phone #? what exactly does that want it for? in case i win a prize?
Doesn't seem to be a way to see the participants yet, but I assume they'll be displayed on the results page once the tourney is underway. However, here is who we have so far: BobFinn Castor27 KaiSeR SoZe Kam underovereup slcrocket fatman510 VecseySux Mooch SSG Roc Paint Manny Kilgore Trout Flyer Fanatic