I used Blackjackapprenticeship.com and found it very beneficial.

I spent 2 to 3 hours training daily. And played in the casino after 1 month.

It's has a very active forum with many new players, has easy to read charts, and the training software is great.

If you decide to not use Blackjackapprenticeship.com, I would recommend the book Professional Blackjack by Stanford Wong.