I've been looking for the same about two years ago. For fortran they are hard to be found and free+for_fortran is next to impossible to find. Visustin was the only reasonable one, but is not free.
Of course nobody wants a flowchart of a whole code, except for bosses asking for it. What they don't tell you is how to place such a flowchart which only fits on an A0 paper into your document.
(My personal opinion is that a flowchart is of no use at all, and less when you make it after having programmed)