India's Hindustan Times published an article in which "highly placed sources" assert that an offline Gmail client is in development.
According to highly placed sources, Google has developed an offline version of Gmail. Gmail Offline will allow users to browse, reply, save drafts and do everything that currently Gmail does in an offline mode even when you don't have an Internet connection.
The writer speculates that the groundwork was set in March of this year with the launch of Google Gears, an open-source framework under which software developers can create offline Web applications.
This can be further evidenced by a Google spokeswoman confirmation that a version of the Google Reader will be made available offline.