Originally Posted by: schmangeThere's a certain amount of 'fair usage' allowed and you'll hear 'close' copies of tunes all the time, especially in things like commercials or comedy movies.
There's also a bit of a grey area where it comes to parodies.

Someone should sue nickleback for making "someday". Anyone who's heard the way you remind me of someday knows exactly what i'm talking about. different freakin vocals played over the exact same instrumental tracks. not to mention, it actually did pretty well. they fit in well with the artists of today's music industry