I dont know if you want free services or subscription but here are some
I listen to the Fantasy 411 on MLB TV, Mike Siano and Cory Schwartz are very insightful and give helpful advice in a friendly manner.
If you want some minor league news then Baseball America is the way to go in my opinion
Rotoworld.com is nice, and if you want some help seeing what certain player values are at that moment then go to protrade and enter the player stock market. If a players pricegoes up it means his value is rising in the eyes of the public and it s a helpful roundabout tool to predict player spikes early.
Those are just a few off the top of my head, some more indepth places like pecota are also available.
Thanks to Alec03 for the awesome sig