I assume you mean VoIP email messages? If so, as far as I know you can't open them right now but they are working on it. I copy my email to a gmail account and when a voice mail/email message arrives I go into my gmail account (it can't be gmail mobile) and you can listen to the message this way.
Having gmail as the middle man also acts as a spam filter so I don't get any junk mail on my pearl.