Anyone with a standard account can choose the option to manage their e-mail even when they're offline. (This can be accomplished by clicking on "settings" and then entering Google's "labs" section.)
After the e-mail box synchronizes with a computer's hard drive, virtually all of Gmail's usual tools become functional offline — except for the ability to send and receive messages. Those chores are handled the next time a computer connects to the Internet.
Yahoo Inc's e-mail service has been able to work without Internet access since last July. To take Yahoo mail offline, users first have to download the company's Zimbra software to their computers. The Zimbra program also can be used to work offline on competing services, including Gmail.
Gmail is making its offline leap through Gears, a Google-owned service that the much smaller Zoho relied on to provide offline access to its e-mail program last year.