LOS ANGELES - Microsoft Corp. is taking another step into the world of web-based computing with a new system it's calling Windows Azure.

Microsoft says it's joining Amazon.com Inc. and other rivals in selling information storage space and computing power "in the cloud," distributed across massive data centers worldwide. That will let companies build web-based programs without having to manage their own data centers.

Microsoft's chief software architect, Ray Ozzie, described Azure to software developers at a conference Monday in Los Angeles. Ozzie said that managing Microsoft's own web sites and web-based programs has made the company adept at anticipating web traffic spikes and knowing when to ramp up some computers and dial down others.