NatWest today released a free mobile application that allows the bank’s customers to check their account balances, view recent transactions and manage their money on the move. But only if they have an iPhone!

While it is fantastic that brands are now flocking to the iPhone, perhaps they should consider developing applications for other mobile handsets too or they could risk alienating large parts of their target audiences. For many brands I imagine that the cost of developing and maintaining an application for several different platforms at once could be restrictive, especially if it is their first foray into the world of mobile apps and their marketing budgets are already looking tight.

But this need not be the case. I recently went along to the launch of Airplay SDK 4.0, a mobile application development and deployment solution. Airplay allows mobile developers to deploy applications with a single click across platforms including iPhone, Android, Symbian, Windows Mobile, and many more. This seems like a much more effective route to targeting your customers, than sticking to one particular mobile handset. No matter how cool it is!