There's no denying the popularity of music creation apps for the iPhone. Just about every instrument you want to play is available as a digital simulation - from guitars to pianos to drums, and even DJ decks - but what about wind instruments? The iMonica app for iPhone from DigitarWorld most definitely fits into this category and turns your iPhone into a digital diatonic harmonica. So, do you blow and draw on your smartphone? Kind of ...

The app presents the user with three options when loaded - Play, Setup and Help. The settings button allows users to change options like the color of the digital harmonica, change the tone to a whistle sound, or try a different key. The other buttons are self explanatory.

To get the feel of the app, you might want to start playing using your fingers to produce notes on the virtual harmonica. Pressing one of the ten hole positions onscreen and lowering the iPhone will result in a blow note being played that corresponds with that position. Similarly, a draw note can be achieved by pressing the appropriate note position and raising the iPhone. There are a number of songs by the likes of Bob Dylan and The Beatles transcribed on the website to get you started, with embedded YouTube videos to show you how the original artists whooped it up.

With the basics down, you could then move your new instrument to where it really belongs - your mouth. Although my smartphone is probably no dirtier than my much-neglected Hohner Cross Harp, the developers stress that the iPhone's playing area should be thoroughly cleaned before being used as a mouth organ, or perhaps covered in plastic food wrap to avoid infection from microscopic nasties.

Once you get used to the somewhat crazy playing style, you'll no doubt be freestyling rather than following pre-prepared notation. The app does appear to be limited to single-note playing techniques, with no obvious way to virtually bend, trill or vamp - so you'll not be able to emulate great harp players like the legendary Sonny Terry, the Maestro Shaky Horton, or the man who helped shape Chicago blues, Little Walter Jacobs. For such expressive playing, you'll need to buy a real tin sandwich.

For wowing friends, making some noise and having some fun, though, the iMonica app looks well worth the US$0.99 cover charge.