/x-tad-smaller>The vocal helper thingy you are talking about is called Auto-tune. You can certainly get some interesting effects from using Auto-tune "inappropriately" The most interesting thing is that for fretless performances with slow glissando, AT will get confused about what pitch it is supposed to be tuning to and bounce back and forth between notes. If you set AT so that is takes a while before it starts correcting a pitch you can actually "fix" a note with out much of the audible artifacts, but you will of course kill the natural vibrato which is such a lovely part of fretless instruments.
If you are recording to ProTools or something similar, try this little idea to add some weirdnesses. Using a plug-in, take an instrumental track and pitchshift it up a half-step. Then apply the Auto-Tune and see what happens. :-) I've had some fun with this.