Amazon has launched a hosted content-delivery network (CDN) service that it first announced in a preliminary test version two months ago.

Called CloudFront, the service joins a variety of other Internet cloud-based services that the company offers via its Amazon Web Services (AWS) unit.

AWS offers a suite of generic computing, payment, billing, fulfillment and Web search services so that its customers, including application developers, Web masters and other IT professionals, can focus on the tasks in which they specialize.

The AWS products are examples of cloud computing, a model in which IT vendors host software and hardware in their own data centers and make them accessible via the Internet. Since clients don't have to install the hardware and software on their premises, they, in theory, can reduce hardware and software provisioning and maintenance costs.

Specifically, CloudFront is designed for distributing public Web content with low latency and high data transfer rates It can be used for things like distributing podcasts, progressive download of video clips, software downloads, delivery of photos and serving up of Web site objects like CSS and JavaScript files.

Like other AWS products, CloudFront will be billed based on usage, without requiring upfront usage or flat fee commitments.

A single API (application programming interface) links Web applications to CloudFront, which has been designed to tightly integrate with Amazon's S3 hosted storage service. CloudFront serves up content from several points located in different parts of the world.

Early CloudFront adopters include Woot, an online store that uses it to serve up photos of its products; and Playfish, which uses it to distribute its online games.