u can find "Blasphemy" on kazaa (keep searching)

but the song used in the anacondas trailer is "Blasphemy 2.0" which is the latest one from Immediate music

there is no chance you can get this one :(
Ok sorry, scratch that audio thing, here's an easier way. As soon as loads up, it will say The Ultimate in Cinematic Production Music is Immediate Music. Go down that page. At the VERY bottom, there are five buttons that say stuff like headlines, licensing, about, contact, and music. Click on Music. When that page loads click on "Browse" and you will find it there under Action/Adventure.