then there is this:
www.atpls.org, also completely free. Seems to have about the same questions (well you can hardly tell exactly, can you) but this one doesn't show you the correct answers up front (unless you just press submit without even trying
)
Seems to be very recent so there aren't too many explanations there yet but I came across some, I guess their aim is not only to list the questions but to provide some feedback/learning tools as well.