Fretboard Logic. I'm surprised this hasnt been mentioned yet.
Also I'll throw in Victor Wooten's Groove Esstentials. http://www.amazon.com/Victor-Wooten-Groove-Workshop/dp/B001DPC4I2
Its labeled as a master class for bassist, but it will blow your mind and make any musician their approach to music and their instruments.
A great video to grab is Victor Wooten's Groove Workshop It's absolutely inspiring to me, and teaches some great tools for all players.
Also recommended: http://www.themusiclesson.com/
Rocksmith is ok. I have it, but it, like any lesson plan, is dependent on the player's dedication, and the game seems to fudge enough to make you feel like you're doing great when you know you screwed things up (that's my experience, anyway).
Scott's Bass Lessons is the bass player's equivalent of Justin's lessons, plus some. It's not free, but it is worth it. Plus, a ton of content can be found outside the pay model - make YouTube your friend.
A free resource - started just this month - is Andy Irvine's Daily Funk Club. Andy's a great guy and good teacher. Lots of energy there.
Also, for inspiration alone, get him Victor Wooten's dvd "Groove Workshop" (also at Amazon) and his book (or audiobook - or both!) "The Music Lesson."
Welcome to the bass!
A great video for bass playing in general is Victor Wooten's Groove Workshop dvd. Also available at Amazon. Great lessons there applicable to all playing.
There are also clips of the workshop on YouTube.
More on the mindset of playing bass than any one specific technique, but I highly recommend Victor Wooten's Groove Workshop or his book The Music Lesson (the audio book version is nice too, narrated by Wooten and features some playing between chapters.)