Yahoo! Zimbra Desktop is an email client (offline) that allows you to receive and send all your emails; Yahoo mail, Gmail, Hotmail, AOL, Zimbra mail and POP3 or IMAP service while you are disconnected from the internet. When you are online, this program will automatically synchronize the data on your server with your computer. You may read your email while offline and create new messages to be delivered the next time you are online.

Even though the program has an awkward and non-intuitive interface, configuring your mail account is very easy. Follow these steps to access your account: Run the program after installation, Click on Setup button, then click on ‘Add new account’. Choose an email provider (Yahoo! Mail, Zimbra, Gmail, Hotmail, AOL, POP or IMAP service)1. Enter your account information: (Email address, password and other account settings)
2. Add additional email accounts: (You may access more than one account including multiple accounts from one provider)
3. Launch Yahoo! Zimbra Desktop:(You may send new messages immediately, but it may take a while to download all data for a large account)

Besides being able to access your different email accounts from one place, Yahoo! Zimbra Desktop also manages your contacts and has a calendar, document editor, task list application and a briefcase tool for storing your attachments. Read more about Yahoo Zimbra [via]