you could try fruity loops. (www.fruityloops.com) - its a complete desktop synthesizer and you don't need any external midi equipment, or other programs to run it. I'm most possitive its available for mac as well as pc. (if you have external midi equipment then you can use it with the program to make your own sound files, etc.) i've never seen any other program quite like it. There's a trial version and a license is somewhere around $40 (various levels of licensing tho. one, i believe, gives free lifetime upgrades, or use to). The only thing you'd need would be a microphone for the singing, which you can use a standard desktop mic. its tone banks are virtually endless, and you can create your own. I've played with the program before, its rather addictive. a friend of mine uses it fairly regularly and when he needs voice, he uses his desktop mic with no problem. E.D.