Traktor DJ for iPad showed us what can be done when you resist the urge to simply shrink your existing software or just slide it under a touch interface. Since its iOS debut, the folk at Native Instruments have spent the last couple of months cautiously considering how best to transplant the same waveform-based interface over to the iPhone. Today, you can find out. You get everything you find in the iPad version, like three band EQ, filters, hot cues and effects --along with the same key, tempo and timbre matching utilities, plus library sharing with the full-fat desktop version. The UI isn't the only thing getting downsized, either: this iPhone-friendly version costs just $4.99 (compared to $20 on the iPad). That should leave enough change to drop a few on party rock anthems.