There are 3 different programs here that support FIGlet for the Macintosh:

o unix-port
    This is a direct port of the UNIX version with all the features of the
    UNIX version, but doesn't have a nice Mac user interface.

o figtree
    This has a nice Mac user interface, but is not a full port and some
    features are missing.

o emaileffects
    This is actually a text drawing program, but it also supports FIGlet
    fonts.