A fresh approach to step sequencing is offered in the cube-like interface of iDrum (V. 1.0.2, iZotope; $4.99). It comes in several editions, which offer genre-specific sample sets for rock, hip-hop, house, and more. You can edit its existing song collections or program your own beats. In addition to drum sounds, you get one-shot bass, guitar, synth, and effects samples. When you're finished, you can send your creations to your computer, but only as M4a-format ringtone files. However, if you own iZotope's iDrum app for Mac or PC, you can export your patterns directly into that. If not, you could, as a workaround, export your pattern as a ringtone, open it in a waveform editor on your computer, and convert it to a WAV or AIFF for use in your DAW.
The iDrum application takes advantage of the iPhone platform; you can tap virtual pads to create rhythms, shake the handset to clear patterns, and use slide and flick gestures to navigate the application's interface. Colorful visuals show the relationship between different sounds in the beat, which allows you to use visual patterns to create new rhythms. With a companion application, beats can also be turned into ringtones for iPhone.