I use binchunker to convert .bin/.cue files to a single .iso file on my Mac. You can obtain binchunker via Macports.
Here's some more info from the manpage:
bchunk - CD image format conversion from bin/cue to iso/cdr
bchunk [-v] [-p] [-r] [-w] [-s] <image.bin> <image.cue> <basename>
bchunk converts a CD image in a ".bin / .cue" format (sometimes ".raw / .cue") to a set of .iso and .cdr tracks.
The bin/cue format is used by some non-Unix cd-writing software, but is not supported on most other cd-writing pro-
image.bin is the raw cd image file. image.cue is the track index file containing track types and offsets. basename
is used for the beginning part of the created track files.
The produced .iso track contains an ISO file system, which can be mounted through a loop device on Linux systems, or
written on a CD-R using cdrecord. The .cdr tracks are in the native CD audio format. They can be either written on a
CD-R using cdrecord -audio, or converted to WAV (or any other sound format for that matter) using sox.
It is advisable to edit the .cue file to either MODE2/2352/2048 or MODE2/2352/2324 depending on whether an ISO
filesystem or a VCD is desired, respectively. The format itself does not contain this feature and in an ambiguous
case it can only guess.