Soon, it may well be easier to list the artists who DON’T have their own branded iPhone app than to list those that do. In the last few days alone, more than 250 artist apps have been launched on iPhone’s App Store by iLike, which is charging bands $99 apiece for developing them.Meanwhile, Kyte has launched iPhone apps for the likes of Lady GaGa and the Pussycat Dolls, Mobile Roadie has taken Spinal Tap onto the App Store, and everyone from David Bowie to BT to Soulja Boy Tell’em have launched iPhone apps letting fans remix their songs. The days when it was just Snow Patrol and Pink ploughing a lonely iPhone furrow are long gone.Launching an iPhone app makes sense right now. More than 45 million iPhones and iPod touches have been sold, meaning a healthy addressable base. What’s more, iPhone apps are cool – the PR benefits alone often pay for the development costs. Yet we can’t help wondering when the people commissioning these apps will start looking beyond the App Store to other mobile platforms.Some stats for you: When Microsoft launches its Windows Marketplace for Mobile app store this Autumn, the company says it’ll work on 30 million handsets from day one; Nokia reckoned its Ovi Store had an even bigger potential base of 50 million users when it launched earlier this year; there are 28.5 million BlackBerry subscribers in the world according to Research In Motion’s latest financial results; and analyst firm Strategy Analytics predicts that 8 million Android handsets will be sold in 2009 alone.Or to cite just one blunt statistic: the same analysts say 273 million mobile phones were shipped in the second quarter of this year. Only 5.2 million of those were iPhones (the number of iPod touches is unknown).See where we’re going with this? Launching an iPhone app is great, but there are hundreds of millions of music fans out there with other handsets, many of which are also capable of downloading mobile applications. So why not target them too?In truth, there are sensible reasons. The iLikes, Kytes and Mobile Roadies of the industry are focused on iPhone right now, for example. What’s more, making an application that runs on dozens of Windows Mobile or Nokia handsets is a more costly and complex undertaking – ask a mobile developer about ‘fragmentation’ and watch their face drop if you want proof.Making apps for non-iPhone platforms can be a pain in the arse, in other words. But that doesn’t mean it’s not a worthwhile pain in the arse if you’re truly looking to engage with your fans.It would be surprising if more artists don’t venture onto non-Apple mobile platforms in the months ahead. They’re all wooing application developers (and by extension the brands that hire them) to launch on their app stores, and Nokia and RIM particularly have a focus on working with the music industry.As an artist, launching a mobile app is about having a presence on your fans’ phones, which they can turn to for news, videos, music, ill-conceived mini-games… Stuff, basically. Having your favourite band in the palm of your hand? There’s an app for that! But why restrict it to a relatively narrow section of your fanbase?Music Ally will soon release our Mobile Music Report, including an analysis of the apps space. For more information, contact Anthony Churchman via our online form.