I know Apple lets people produce and release songs with their samples no problem
Uhh, no. Apple doesn't own the music they stream/sell. If you use samples, you need permission (or have to pay) from the original creators/writers. That is if you want to release the music commercially. If you just want to create youtubes, etc, and have your friends pat you on the head, then its no big deal.
To get on Spotify, you have to release your music through some type of service (like CDBaby or Tunecore). If you don't own it completely, then you have to register the correct writers/originators.
Pandora is worse to get on to - you must submit your previously-written music to them, and then they decide whether they want to include it or not. They are supposed to be going to an 'open' system, but haven't heard any more about it.
My reverbnation site: http://www.reverbnation.com/mikebirchmusic
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Youtube: http://www.youtube.com/mikebirchmusic
Facebook: http://www.facebook.com/mikebirchmusic