bismark has released Music2Bus, a music player for iOS compatible with Audiobus, the inter-app audio routing system.
You can send your Music (iPod) Library to all Audiobus compatible apps, and play them in various ways.
For example, You can play your favorite part of your favorite song in Apple's GarageBand app, by using Music2Bus and Audiobus.
Additionally, a 5-band equalizer is included.
Please note this app can not play protected music content.