There is a lot more material out there nowadays...I personally used "Pass Perfect" and I thought it was pretty good. It's not too hard...105 Q's...need a 70%.
there's a whole bunch of free content online if you search google for "free series 56" - review guides, outlines, videos, etc. etc.
I used Pass Perfect. I felt like "most" of what was asked was covered, at least 85%. It'll get you through if you study hard. Wilt
This has been discussed in this thread: http://www.elitetrader.com/vb/showthread.php?s=&threadid=225634