Can you split audio on iPhone earphones?

Hey,

Does anyone know if you can actually split audio properly using iPod headphones? I remember there being some tracks I've downloaded which sound like different parts of the songs only play in the L earbud and other parts in the R earbud but is this something that only plays exclusively in either earphone or is it just an effect?

Can I create a track in garageband that can split the audio?

Message was edited by: our_tone