I found an excellent article for this subject under this following link.
http://tomyeah.com/howto-convert-bin-cue-to-iso-in-mac-os-x/
Just in case if the other site goes down (which has happened a few times in the past) and I lose this wonderful information, I had to copy paste the comments here.
I’ve found a freeware solution, using the open source software “binchunker”. It is available on Macports. Use the terminal to run these commands:
sudo port install bchunk
bchunk IMAGE.bin IMAGE.cue OUTPUTIMAGE.iso