Akai Professional has released SynthStation (App Store link), a $9.99 music production app for iPhone and iPod touch:
Transform your iPhone into a music production studio. SynthStation transforms your iPhone, iPod touch or iPad into a portable music production studio for mobile music creation. SynthStation gives you three powerful synthesizers for creating and modifying sonic textures used for melodies, chords, and bass lines. Built around Akai Professional’s history in synthesis and drawing on the newest MINIAK synth, SynthStation sounds great and offers wide-ranging sonic flexibility with its virtual analog synthesis.
From the moment you start SynthStation, you’ll know your way around. It is jam-packed with tools to help you create music with the convenience of your touch screen and each section works the way you work. With SynthStation, you can create and save sequences and complete songs. The app contains three different three-oscillator synths and a range of drum kits you can sequence and mix right in the SynthStation. For creating melodic and accompaniment parts, the SynthStation contains an arpeggiator with preset patterns, built-in effects and filters, and an XY touch control interface for expressive control of key parameters.