I found an old uif file from my old Windows machine that I needed to use on my Mac. After a bit of sniffing about, I found this nifty program that does it very easily – http://vafer.org/projects/uif2iso4mac/
To use the prog, simply install as you normally would, fire up uif2iso and then select File->Open. The GUI is pretty sparse, so you won’t see anything open on the screen when you fire up the app, which is a little confusing at first.
Apparently the program is cool with converting files up to 2GB. My file was not that big, so I can’t say. What I can say is that it worked just fine and I was able to mount my new ISO and access the files I needed without any problems.