If you are away from your office and have internet access, maybe on holiday or at a clients site, you can still check your email using Tuska WebMail
Go to http://webmail.truska.net and enter you email address as the username and your password.
You will then be presented with your in-box and all emails still on the Truska server.
You can do all the usual tasks like Reply, Forward etc from here as well as manage an address book and your AutoResponders.
The emails available will depend on your client (Outlook, ipad , laptop etc) settings but it is often set to hold ail for 1 week.
If your are using IMAP all your email should be here.