I\'ve installed Devise for my Rails app (3.0.1) and it\'s mostly working. I just can\'t seem customize the mailer views.
If you are interested in not using Devise's default usage of ActionMailer and would instead like to send customized emails with an API from a service like SendGrid, Mailgun, or Postmark you will need to create a custom Mailer that subclasses Devise::Mailer and overrides its "notification" methods.
Here is an example using Mailgun.