Here is a link to the transcript of an Australian Federal court case from a few years back. It details (if you can sift through all the legal jargon) the case of a bunch of guys that released an album without acknowledging samples.

IDIOTS!

They got completely shafted (and rightly so) and have been ordered to pay a total of USD $128,398.23. in damages and legal fees. Let this be a warning, but i assume none of us are quite as stupid as these twats.

Check out the list of tunes they sampled.