Google Inc. is preparing as early as Tuesday to unveil a new online music service similar to a service recently launched by Amazon.com Inc., according to people familiar with the matter, a move that escalates the battle to create the next generation of Internet businesses for storing and listening to music.

Google, like Amazon, hasn't secured licenses from the four major recorded-music companies, according to these people, and is likely to include a system that functions much like a remote hard drive.

Users...