It lets you search and download music at an amazing speed, using either your 3G or Wi Fi connection (Edge is also supported). It also has the ability to add your downloaded music into your iPhone / iPod Touch music library, enabling you to instantly listen to it from the default music player without iTunes or any computer required!
MewSeek Pro can be downloaded from the BigBoss Cydia Repository. The application costs $6.99 to register. The unregistered version lets you listen to as many songs as you want (streaming) but only lets you download and add a maximum of 15 songs to your iPod's music library.