Nero has it's own virtual drive app as well.
Then there's CD Space, which I am a big fan of.
But one thing you need to be careful of, at least with Windows 98SE, is not to have too many virtual drives defined at the same time, because once you pass a certain limit, you can have trouble with certain audio players like Musicmatch Jukebox and even Windows Media Player. I ran into this once. I think the limit was 3 virtual drives IIRC (not CD images, you can have as many of those as your hard drive will hold). But it may have been 4 or 5.
But if you have a problem, you'll know it, and just delete one virtual drive at a time until your media player works again.