I want to make mashups but it is such a hassle to get the acapellas and instrumentals of songs.
Does anyone know an easy way to get them for free? Also, on a mac, what application should I use to make the mashups?

Also if you have a sec, check out the mashup I made and if you could, give me some feedback.
http://www.youtube.com/watch?v=Xx6_hjPmogA

Thanks!