Recently this app has been updated to version 1.0.1. This new version fixed a bug that caused playback to resume after a telephone call even if it was paused before. You should note that this app requires newer iOS devices with multitasking support. This app can automatically search the track for you in the iTunes store. Also this app supports your headphone remote controls.
Eavesdrop 1.0.1 is compatible with iPhone 4, iPhone 3GS, iPod touch 4G, iPod touch 3G, and iPod touch 2G running iOS 4.2 or higher. This app is available through the App Store in the Music category. It costs $1.99 USD. You can download and get more information about Eavesdrop 1.0.1 from here. [iTunes Link]