As Apple passed another milestone in mobile with 3 billion app downloads, Google stepped up its competition in the Smartphone market with the launch of its Nexus One phone. Obviously, this uses Google’s Android operating system, also in use on an increasing number of handsets, including the much hyped Droid phone from Motorola.

The phone is initially sold directly from a Google website, with consumers able to choose their preferred operator for the $529 device (a $179 2 year T-Mobile USA deal is also available, more coming soon including Vodafone in Europe).

But is it an ‘iPhone killer’? It’s certainly close in size and shape to the iPhone and boasts finer screen resolution and a removable battery, plus a number of innovations including free GPS navigation. However, with a still limited Android app store and no bundled ‘iTunes’ equivalent, the iPhone may well still have more of its nine lives to use up…