Google unveiled on Thursday its plans for a store where mobile users can find Android applications, a concept similar to the iPhone's App Store.

The first handsets running Android, expected to appear later this year, will include a beta version of the Android Market, Google's Eric Chu wrote in a blog post. Initially, users will at least be able to find free applications there. After that, Google expects to update the Market to allow users to buy and download paid content.

The Market will feature a feedback and rating system similar to that used in YouTube, Chu said.

Developers can add their applications to the market by registering as a merchant, uploading the content and publishing it. Google expects to add features for developers after the initial launch, including a dashboard where developers can find analytics information about their content. Developers will also be able to upload different versions of their applications that might work better on different devices.

Android followers have wondered how Google might support application distribution. Its Android Market is a similar concept to Apple's App Store, but differs in some ways. For instance, because all iPhones run on the same software, developers don't have to create different versions for different phones. Android is open, and handset makers may decide to include different hardware capabilities or opt not to support all Android features, which has an effect on the way applications work.

Historically, the mobile market has struggled with how to best sell and distribute mobile applications. Prior to the iPhone, the best way for an application to become widely used was for a developer to convince an operator to pre-load it onto a phone, a challenging accomplishment. Mobile phone users only very seldom download applications to their phones.