Google Inc. wants to offer consumers a new way to store their files on its hard drives, in a strategy that could accelerate a shift to Web-based computing and intensify the Internet company's competition with Microsoft Corp.

Google is preparing a service that would let users store on its computers essentially all of the files they might keep on their personal-computer hard drives -- such as word-processing documents, digital music, video clips and images, say people familiar with the matter. The service could let users access...