Excellent source for tutorials and lessons.  Use tabs at the top to switch between NXT and EV3.  Good range of basic to advanced.

 Free downloadable program produced by Lego.  Virtual bricks and computer aided design allow even more limitless imagination.  Also a prime tool to build and evaluate manipulators;)

Can't say enough about the resources for FLL teams here.
Click on downloads and get the software.  Slew of interesting stuff inside the world of Lego.