Amazon has announced three enhancements to its Cloud Drive and Cloud Player services, which launched earlier this year: a storage plan with unlimited space for music; free storage for all Amazon MP3 purchases; and iPad support for Cloud Player for Web. The Cloud Drive allows users to upload files to a digital drive that can be accessed from a range of devices with online connectivity. Cloud Drive already offers customers 5 GB of free storage space. Now -- for a limited time, according to Amazon -- $20 a year will buy unlimited space for music and 20 GB for other file storage.