Just so you know, it would MUCH easier if people went to this link:
http://baseball.fantasysports.yahoo.com/b1/register/createjoin?.scrumb=
The one you provide just gives an error cuz it's thinking the person is in the league already.
People can click on that link above, hit the "Join League" button, then submit their info, including the password (ask Frinky) and the League ID Number, which is 274328.
Might wanna update the first post. ;)