You can still access your old DreamHost e-mail account using our WebMail interface, just at a different address:
Simply enter your full email address and password and you're in! This should only be used to view your old messages, as that's all you can really do in there.
Also, a little more information about what Scott was talking about can might be helpful. You will need to grab one piece of information from your DreamHost Web Panel (https://panel.dreamhost.com). Log in and click on the "Account Status" link in the upper-right section of any page. Find "Your Email Server" and take note of the name there.
Then, when configuring your e-mail account in the e-mail software, you'll need to use the following for your Incoming Mail Server: "a1.balanced.YOUREMAILSERVER.mail.dreamhost.com" where "YOUREMAILSERVER" is the value you noted from the "Account Status" in your DreamHost Web Panel above.
--DreamHost Tech Support