I've been using them for 5 years, and I swear by the Fantistics guys (http://www.insiderbaseball.com
for those who haven't been there).
It's not free, but to shell out a few dollars ($35 for returning members), their software saves me countless hours. Although I have had much success using their projections, personally, I have strong feelings on some players and like to make my own projections on those players...with their software I can change their projections and have the program produce my own roto values.
On top of that they have excellent daily reports during the season.
Boston Mudslingers League