We built Voice Email specifically to spice up the users email. Basically the app will take your written emails and read them out loud to the receipent. The real benefit to the app would be allowing the receipent to multitask while listening to incoming emails. The 25 different voice selections can definetely help you select the perfect voice mode for your email.
http://itunes.apple.com/us/app/voice-email/id474703606?mt=12
http://itunes.apple.com/us/app/voice-email/id474703606?mt=12