Well, you missed by about two months. The[url='http://www.froglegfestival.com/']Fellsmere Frog Leg Festival[/url] is held in January - about 20 miles south of Melbourne.
As far as frog legs on the menu in restaurants, I haven't seen them in awhile. There was a place called Wally's Pad
that served them, but it closed down a few years back.
On the other hand, you are maybe the first person I know of who ever associated Melbourne, Florida with easy accessibility to frog legs. Maybe I am just running with the wrong crowd, but I have never been with anyone who was looking for frog legs here - maybe that's why Wally's didn't make it!