GOOGLE is beginning to bridge the “app gap” between its Android smartphones and Apple’s rival iPhone, as figures reveal users are downloading one billion software applications per month on each of the two platforms.

A vibrant ecosystem of apps – small, cheap downloads offering add-on features – is seen as vital to customers’ smartphone choices, as market leaders Apple and Google face renewed competition from Microsoft and Nokia.

In a blogpost yesterday, Google touted a milestone of 10 billion apps downloaded from Android Market since it launched in 2008, up from six billion in June, with the current growth rate at one billion apps per month. Downloads of apps for Microsoft’s Windows Phone 7 trail by a considerable distance.

Mobile developers say that Google still lags far behind Apple in generating revenue from apps, in spite of Android’s larger user base.