Their report, tapping a "source familiar with the matter", suggests that while 5 GB of storage will be free, users will be able to pay for up to 100 GB worth of Google-based storage. As well as hosting the data, we can expect some advanced search tools to complement the storage.
As for a release today, it seems likely. Engadget reports—and I can confirm—that the Google Docs storage quota has been bumped up to 5 GB, which suggests a Drive launch is imminent. [Reuters and Engadget]