To me the best vocal samples come up when you least expect them when you're watching a movie or video. I watch dvd's on windows media player and when I come across a vocal sample I like, I record it in Sound forge. I've built up some unique vocals from various movies. One of my favorites was taken from"40 yr old Virgin" If you're talking about vocal samples that are part of a sample, that's relatively easy for me since many of my favorite sample chops will have vocals in them anyway. That comes from the RZA, DJ Muggs, 9th Wonder chopping style I've come to love. Some of the best parts of the record to sample have vocals in em. They can also make the track more soulful.