As anticipated, Google today officially unveiled the Nexus One smartphone, an Android-based mobile phone which Google will both sell directly to customers as well as through partner T-Mobile.

The phone features a 3.7 inch touchscreen with voice-command features and the latest version of the Android operating system-Android 2.1-which features updates to Google Voice, images and graphics, and other Google applications. It's music capabilities are much like that of other Android-based devices, which is to say it will support whatever music apps are available for users to download via the Android Market app story. One interesting upgrade though is that Google will soon expand the number of apps users can store on Andorid phones.

More interesting is that the device is available "unlocked" - meaning buyers can choose the mobile network of their choice rather than buy it through the carrier directly - for $530. For now, it only works on T-Mobile's network, but other operators like Verizon and Vodafone this spring are expected to support it in the near future. T-Mobile is also selling a version of the phone for $130 along with a two-year service contract.

Google hopes to shake up the mobile industry by implementing a system similar to that in Europe, where consumers buy the phone they want and then choose their service carrier. In the U.S., carriers sell phones directly to consumers with a heavy subsidy made up through multi-year service contracts.

Google hinted that the Nexus One was just the first of many phones it will sell directly to consumers, working with additional development partners to do so. The Nexus One was created in conjunction with mobile phone manufacturer HTC.

But perhaps the bigger indication of the Google-sold Nexus One is a ramp up of its competition with Apple. Google now has an answer to Apple's iPhone, and is said to be shopping around for a music service after losing the bidding war for Lala. Apple, meanwhile, responded to Google's acquisition of mobile advertising service AdMob by buying AdMob competitor Quattro Wireless.