Fantrax has a free option available. It all depends on the settings that you are using, but if you have a proboards site established for league functions and Fantrax is just for scoring it might be a good idea to check it out. Good luck
Just in case team preferences are keeping someone away, Phillies and Tigers are now the only available.
The league mimics, as closely as possible, MLB. 25 man active rosters, coincinding with 40-man roster and 90-man minor league roster. Waivers system, Rule 5 draft, Amateur draft, and more add to the realism.