Yes MS Flight is free, I downloaded and played it but it was nothing to write home about so I uninstalled it. You have to pay for extra addon planes and scenery and stuff to make it better, so I might just as well stick with fabulous FSX..
Incidentally here are yesterdays viewing figures showing how many people were looking at each subforum at any one time, FSX is obviously king..
FSX (164 viewing)
FS2004 (86 viewing)
FS2002 (20 viewing)
MS Flight (7 viewing)
Military Flight Sims (2 viewing)
X-Plane (0 viewing)