OK, I tried. I can't get in two different ways, one probably because I mainly use my gmail account this days, if that somehow matters, and I'm not sure I didn't use it last year too - I cannot get in because "you don't belong to this league".
Secondly, I can't get in through my yahoo account because "We did not find results for: http://baseball.fantasysports.yahoo.com/b1/190478.
Maybe we have to get invites?
I may still have my signup stuff for last year, to check which email I used.